Celtic Kane

Determine Your Tolerance Results
  • Your estimated BAC is not available yet
  • Your estimated time to drive is not available yet
  • Your estimated time until sober is not available yet
Metabolic rate:
Elapsed time: hrs
Determined Total Consumed Alcohol
Percent alcohol: %
Total servings:
Alcohol History
[no alcohol added]

Purchase a Breathalyzer

BACtrack S80 Pro Breathalyzer Professional Edition

This online BAC calculator is good for estimating your BAC level, but your actual BAC will vary depending on a host of different factors, such as your hydration status, recent meals, fluid intake, kidney function, and much more. If you’re interested in buying a breathalyzer to get a more accurate estimation, I would highly suggest the model listed to the right.

Buy a Breathalyzer at Breathalyzer.net

BAC Chart Values
0.00 – 0.03% Normal behavior, no impairment
0.03 – 0.06% Mild euphoria and impairment; decreased inhibitions
0.06 – 0.10% Buzzed, euphoric, increased impairment
0.10 – 0.20% Drunk, emotional swings, slurred speech, nausea, loss of reaction time and motor control
0.20 – 0.30% Confused, nauseated, poor mentation, blackout
0.30 – 0.40% Possibly unconscious, unarrousable, loss of bladder function, risk of death
Above 0.40% Unconscious, coma, impaired breathing, risk of death

Important Notes

  • If you’re typing in a custom percent alcohol, remember that the proof of an alcohol is double the percent (e.g. 80 proof alcohol is 40%)
  • If you’re entering a mixed drink, only count the number of shots you put in (not the drink’s total volume)
  • Everyone is different — BAC calculators are merely an estimate. A breathalyzer or blood test is the only way to have an accurate measurement.
  • This calculator assumes the legal limit for driving is 0.08% and 21 years old. Please note that the legal limit for driving may vary depending on state/country and your age.
  • All calculations are based on the US Department of Transportation.

  1. Taoiseach denies being drunk on radio!!!! - Page 128 (September 14, 2010)
  2. August 2010 | Health Action Trust (December 10, 2010)
  3. to drink or not to drink that is the question..... - PPRuNe Forums (August 2, 2011)
  1. celtickane
    April 9, 2009

    Please note that I just made a bugfix to the Javascript — the calculator was making an incorrect conversion to kilograms (if kilograms were selected). The bug is fixed now.

  2. not right
    April 9, 2009

    4 typical mixed drinks in one hour = 0.451?


  3. celtickane
    April 9, 2009

    Depends on how strong the drink is. If you’ll note the percent alcohol, you have to type in the number of shots into the drink, not the actual volume of the drink. For example, if you had a “typical mixed drink” with 2 shots, you’d type in (2) single shot(s), rather than the entire volume of your mixed drink.

  4. celtickane
    April 9, 2009

    I removed ‘typical mixed drink’ from the drinks list — it was unclear whether you add the volume of the mixed drink or the volume of the alcohol added. To calculate mixed drinks, just add in the volume of alcohol added.

  5. LegalEagle
    April 9, 2009

    You should amend this program to account for different laws in different countries. The legal limit in many parts of the world is 0.05, not 0.08 like in the USA, so you could be liable for a lawsuit for giving misleading information in the “time until you can drive” column. Failing that, you need to add a legal disclaimer.

  6. frank
    April 9, 2009

    Inaccurate. Th heavier the drinker you are the slower alcohol metabolizes in your system. You won’t *feel* drunk sooner because of higher tolerance.

  7. Sir Drinksalot
    April 9, 2009

    Great calculator, good layout

    You could make thousands and thousands of dollars.

  8. celtickane
    April 9, 2009

    While it is true that alcohol tolerance increases, the hepatic metabolism of alcohol also increases. Over time, a heavy drinker will be able to clear more alcohol per hour than a normal drinker because a heavy drinker’s liver will induce more enzymes to break down alcohol.

  9. Kevin
    April 9, 2009


  10. sara
    April 13, 2009

    hear, hear!!!

  11. Nathaniel
    May 22, 2009

    Great page. Could you go into more detail on the metabolic rates you have listed to choose from. Can the human body actually metabolize alcohol that fast ie: “frat boy”

  12. AA :D
    June 19, 2009


    My company does occasional breathalyser checks, due to 0.00% tolerance.

    A mail was sent out today, regarding someone being fired because they were 0.25% over the limit. However, they didn’t say which unit of measurement was used. Is B.A.C always used for breath tests ?


  13. sal
    July 25, 2009

    This is the best! It may be inaccurate in many ways but generally it gives a good idea to people who have no idea how drunk they are. It is also useful if you are planning to get drunk and want to know how much to drink to get the desired feeling. Which may sound stupid but it stops overdoses.

    Thanks for this

  14. Casey J Putnam
    July 27, 2009

    This bac calcutator is fairly competant.The best online calculator I have seen is The fatal vision bac, were they calculate your bac and then give you a graph of the time you started drinking,to the time you will be completly sober

  15. Happy
    August 6, 2009

    Very impressive. I was originally tempted to agree with the fellow who said that your tolerance doesn’t affect your BAC. A high tolerance makes you more in control at a high BAC, but I didn’t know that the metabolism develops to process alcohol faster for regular drinkers. The veracity of the calculator can by seen by choosing “0″ as the time. Then the BAC result IS independent of tolerance selection.

    I’m working on some drinking related tools too. I have a long ways to go to reach your level of sophistication. Thanks for linking to the math. – Happy

  16. joe
    August 13, 2009

    I think the calculator is great and very acccurate. I think a question section for answers would be great. the calculator is good for drinks. what if you have a meal in the middle? If food slows down the ingestion of alcohol into the system, how do you use the calculator?

  17. Chadius DelGraco
    September 6, 2009

    I have access to a PBT (personal breath tester) and I will say this is the best calculator I’ve found online. The results are with in .013 of the actual tester…also I am always sober before the weekend warrior (ave drinker) should be. Maybe I need to up my level to the next one? lol

    Thanks for the great calculator…

    Chadius DelGraco

  18. bowlkilla
    December 15, 2009

    I was wondering if the amount of 1 shot is considered 1.5 oz of hard liquor for this calculator?

  19. celtickane
    December 15, 2009

    Yes, 1.5 ounces of hard liquor is one shot.

  20. Laura
    December 20, 2009

    I’m just wondering if you know of how a drug like Clonazepam (it’s supposed to ‘taper’ down BALs by competing with the breaking down of alcohol) factors in. If you know of any info on this please post.

  21. celtickane
    December 22, 2009

    The metabolism of clonazepam and ethanol/alcohol are completely different — clonazepam does not interfere with the breakdown of alcohol. Benzodiazepines, like clonazepam, can be used to prevent alcohol withdrawal because they both work in a similar way (GABA receptor).
    If clonazepam is taken with alcohol, it won’t affect the BAL, but it will increase the effect of both drugs (e.g. increased sedation and decreased coordination). In other words, taking both together isn’t a good idea.

  22. Frat Boy
    December 22, 2009

    How many onces are in a kraft of wine. and how do you calculate if you drink two different items in the same time frame, like wine and shnopps.

  23. Robert
    January 4, 2010

    This is the best BAC calculator I’ve seen, for sure!

    How does weight work, though? I can see why there would be a difference between smaller and larger people, but what if the weight difference is from fat and not inherent body size? You hear around gyms that fat isn’t “metabolically active,” but does it count for BAC calculations?

  24. Laura
    January 14, 2010

    There is a guy whose living with a female alcohic (she’s light so I entered 120 pounds). He says she drinks a 750ml of Vodka a day and has been doing it for 7 days straight. So I entered 16.9 times 7 and 168 hours. The interesting thing is that for an alcoholic the BAC comes out to be 0. But for a heavy drinker the BAC comes out to be 1.64. Is this a bug, then?

  25. Marilyn
    February 23, 2010

    Can the drug clonazepam 05 Mg increase a blood alcohol count?

  26. celtickane
    February 24, 2010

    No, it wouldn’t have any effect on the numerical BAC level, but it would increase sedation and CNS depression as if the BAC level was higher.

  27. Jade
    March 11, 2010

    This is such a great tool! It is so much easier and cheaper to use then buying a home breathalyzer. I had an officer friend of mine use his hand held breathalyzer to compare with this and it’s pretty darn accurate. No more having parties and worrying about my guests driving home impaired even a little. Thank you much.

  28. Geoff
    March 12, 2010

    I’ve been using this for years, I find it to be pretty accurate. I like the changes, one thing you might want to consider adding in the new alcohol history section is the alcohol % of each drink. Keep up the good work!

  29. celtickane
    March 12, 2010


  30. Andy
    March 22, 2010

    This seems to assume I consume all the drinks at once, and then stop. Wouldn’t I be drinking more gradually, and have a higher and more consistent BAC?

  31. celtickane
    March 22, 2010

    The elimination rate of alcohol is linear (zero order kinetics), so it doesn’t matter when you start/stop. If you drink three drinks in two minutes or over two hours, your BAC will be the same after three total hours. Granted, your “maximum” BAC will be higher if you drink faster, but over an elapsed period of time, you’re still putting in the same amount of alcohol and eliminating it at the same rate.

  32. frank
    March 24, 2010

    Stupid question how would I determin weather I would be considered a frequent or heavy drinker?

  33. celtickane
    March 24, 2010

    There’s no “number of drinks per week” cut-off or anything like that because everyone’s results will vary depending on a variety of factors (e.g. level of hydration, recent exercise, age, percent body fat, etc.) In response to your question, it’s a subjective call — you can try both and see how your results vary.

  34. brucek
    July 3, 2010

    I was ‘checking’ the math’ from the USDot pub. in 6): 128 lb male drinking 1 12oz can of 4.5% by volume beer and got a ’0 hr.’ BAC of ~.03 which is what USDOT got and what the BAC calculator here shows. However, in 2) of the DOT pub, it says that %volume (/100) of alchohol should be multiplied by the specific gravity of ethonol = .79. Thus, the DOT example seems to give BAC by volume rather than BAC by weight. Am I missing something here or is the example incorrect? In CA, BAC is specifically stated as grams/deciliter (weight).

  35. Chadillac
    July 28, 2010

    Please add “16oz pint” to your “total servings”

  36. Who
    August 9, 2010

    You should add ml as a unit since that is how most hard is sold 50ml, 750ml, etc.

  37. Louise
    August 13, 2010

    For reasons I choose not to share I can say that this is hands down the best BAC calculator on the net

  38. Janice
    August 16, 2010

    So if I started drinking around 8:45pm and had my blood tested for a possible DUI at 3:00AM, would my elapse time be: 6 hours and 15 mins?

    Or if I had 1 drink at 8:45pm and then had a new drink at 12:30am, what would be the elapsed time?

  39. Erik
    September 6, 2010

    Your start time is always the time you had your first drink. If you consumed both drinks in less than a minute, for instance, your total BAC would be higher at its peak,…however, whether you drank them both at the same time, or if you drank them fours apart,…you still only drank two drinks. You eliminate them at the same rate. If you drank that first drink at 8:45pm….and depending on what it was, lets say it brought your BAC to .08. The body starts to metabolize @ .015 a minute on average. By the time you have that next drink @ 12:30am, your BAC would have depleted down to .02,…..then you drink that second drink and lets say that drink ups your BAC to another .08. That means at 12:30am, after you drink that second drink…..your BAC is @ .10 The body is always metabolizing the alcohol even while you are still drinking.

  40. Erik
    September 6, 2010

    That last post should have read “.015 an hour” ….not a minute.

  41. b
    September 18, 2010

    does frequent drinker or fratboy really make that much difference??? does alcohol metabolize faster for heavy drinkers?

  42. celtickane
    September 19, 2010

    Yes – the body will upregulate its alcohol metabolism in response to more frequent exposure to alcohol.

  43. Pat
    November 1, 2010

    I weigh 120lbs and ive had 15 12oz beers in 7hrs or less and it says that i should’ve had a BAC of 0.342% and I was just feeling buzzed if that. My friends who were’nt drinking at all couldn’t even tell i’ve been drinking besides the fact i smelled a lot like alcohol. Does this mean I have really good genes?

  44. biasblinds
    November 5, 2010


    First of all it all depends on the percentage of alcohol the drink is. You say you have had 15 beers, but they could have had a really low percentage of alcohol…

    Also the amount of protein eating before or during your drinking duration greatly effects the speed of the absorption of the alcohol.

    Lastly if you are a constant drinker compared to a rare drinker, your body will change to how quickly it metabolizes the alcohol.

  45. Adam Roach
    November 6, 2010

    If this is true, how would you have “good” genes?!

  46. b
    December 12, 2010

    whats a good way to judge which type of drinker you are…. would heavy drinker be someone who drinks three times a week or how would you describe each one

  47. Todd S
    December 12, 2010

    How soon after drinking will alcohol be absorbed in ones system? According to the calculator, as soon as some one swallos a drink, ( even 1 minute) its absorbed in their system. This doesnt seem right. If I drink a glass of wine, then IMMEDIATELY blow in a breathalizer, will the reading be the amount of alcohol in my seliva or in my blood?

  48. celtickane
    December 12, 2010

    Absorption is dependent on several factors, primarily the amount of food that has been ingested with the alcohol. If you were to immediately breathalize yourself after drinking, it would read artificially high because you have alcohol in your mouth. Because a breathalizer works by detecting the alcohol in your respirations, you need to wait 15-30 minutes after ingesting alcohol so that your mouth won’t have any residual alcohol to alter the reading.

  49. questioner
    December 17, 2010

    I have a question. Let’s say hypothetically a person had 10 drinks (we’ll say shots as 40%) in a given night and we want to know if they will be sober in 10 hours (using “heavy drinker” and weight of 200 lbs).

    At 10 shots and 10 elapsed hours, bac is .000 (sober after about 8 hrs)
    If you enter 3 shots 3 hours, or 7 shots 7 hours, both yield .000
    But if you enter 7 shots 3 hours, then 3 shots 7 elapsed hours, it yields .004

    Same amount of elapsed time and consumption quantity, but very different results, what is the reason for this?

    Also, could you give a better idea of general drinking habits for individuals at each level? I realize this is quite subjective, but it’s difficult to decipher, particularly for the differentiating between frequent, heavy and ‘frat’.

  50. Al Thomas
    December 31, 2010

    I drank last night between 11:00 pm and midnight I stopped drinking at exactly 12. I am not sure if how many drinks I had it is between 6-8 I would guess. I have to do a breathalyzer tonight by 7:00pm. So it will roughly be 19 hours since my last drink. Will I pass? it needs to be 0.00

  51. T
    January 6, 2011

    Is elapsed time from the first drink or the last?

  52. celtickane
    January 6, 2011

    Elapsed time from the first drink

  53. kolby
    February 13, 2011

    ok i had roughly 12 beers and a 1/2 pint of liquor and a glass of wine in 13 hours then waited about 7 and had another 6 beers its been about 19 hours since i had anything to drink i am 160 pond male and consider proballly a heavy drinker (at least between frequent and heavy) how in the world do i figure my bac?

  54. kolby
    February 13, 2011

    my 1st drink and my last drink were roughly 22 hours a part…. i had 200 ml of 40% alcohol a glass of wine 13% and 11 beers 4.15% slept 7 hours and then had another 7 beers 4.15% and quit about 20 hours ago total time 40 and 1 hours… how in the hell do i calculate my bac of of all that?

  55. kolby
    February 13, 2011

    please help me figure out my bac i had 11 beers 4.15% alcohol, 200 ml of 40% alcohol, and a 6oz glass of wine at 13 5 alohol in 13 hours. Slept 7 and then had another 7 beers at 4.15% alcoho. lts its been another 20 hours how in the hell do i calculate my bac out of all that its been 40 hours total elapsed time since my first drink and was 20 hours 20 elapsed time from my first drink till my last?

  56. saluwas
    February 14, 2011

    really good calculator. is it downloadable? thanks

  57. celtickane
    February 14, 2011

    Unfortunately, there isn’t a mobile or downloable version at this time.

  58. bob
    February 21, 2011

    The calculator is quite good and correlates within .003 of actual measurements that I get with a new Alcoscan AL7000, which itself has a 10% margin of error. If you give yourself at least a .020 cushion, using this calculator should be safe. That is, if the calculator shows less than .06, you are probably not going to blow .08. But the cops could still give you a DUI charge if they feel like it.

  59. John
    February 27, 2011

    Why would you want to? Your car keys should be locked up anyway, so doesn’t really matter what your bac is, you are too drunk and foggy to drive for at least 24 hrs.

  60. Dani
    March 6, 2011

    This I the best thing ever never missed a bac while usin this thanks for the people who made it

  61. dylan
    March 13, 2011

    okay i had 15 beers in 7 hours…. its been 15 hours since last beer and 22 since first. which figure do i enter into bac calculator? doesent my body eliminate alcohol as im consuming it?

  62. celtickane
    March 13, 2011

    Enter 22 hours — as long as you don’t fully eliminate all of the alcohol you’ve consumed, the calculator will show you your BAC from your first drink.

  63. Graham
    March 14, 2011

    I have a couple questions. If I on average drink a 12 pack every night and have done so for 5 years, would that constitute a “heavy” drinker? I weigh 150 lbs, and had 12 pints of beer between 4pm and midinght and also ate 2 6inch sub sandwiches while drinking. 20 hours have elapsed since my first beer and 12 hours have elapsed since my last beer. Inputing Heavy drinker results in a BAC of .00, frequent shows a current BAC of .139. Huge difference. Should I split the difference between the 2 results?

  64. celtickane
    March 14, 2011

    There’s really no good ‘rule of thumb’ for determining your alcohol metabolism. Unfortunately, your best bet is to get a breathalizer — this BAC is only for rough estimation.

  65. Alcohol and Drug Counselor
    March 24, 2011

    This calculator is wrong. It assumes that tolerance has some effect on BAC level by using the different categories in metabolic rate. Tolerance does not work that way. Tolerance does not have an impact on BAC the way that Gender, Body Size, Rate of consumption, type of alcohol, quantity of alcohol, and body composition. Assuming all other things are consistent, Someone with a tolerance will still have the same BAC level they just won’t get the same warning signals (i.e., euphoric effect, alcohol induced vomiting, alcohol induced blacking out.) that someone without a tolerance will experience.

    It is extremely risky count on if you are choosing a high metabolic rate like frat boy. For example keeping everything the same the difference between Frat Boy (.86 BAC)to Cheap date ( .00 BAC). This is flawed tolerance does not lower your BAC it lowers the response your body has to your BAC. Your body is more “tolerant” to alcohol in your blood (Blood Alcohol Concentration=% of alcohol in your blood) but it is still there and will still come out of your breath when you teak a breathalyzer for a police officer. BE CAREFUL USING THIS!!!

  66. celtickane
    April 4, 2011

    Actually, tolerance is both. Someone may be tolerant and be functional at higher BAC levels. In a similar fashion, however, individuals with chronic alcohol use will also have induction of the hepatic enzymes responsible for metabolizing alcohol. In other words, tolerant drinkers will both be able to tolerate a higher BAC with fewer effects AND have increased metabolic rate.

  67. superdude
    April 23, 2011

    you guys shouuld definantly make one..this is the most accurate one on the whole internet

  68. superdude
    May 5, 2011

    This is the most accurate bac on the internet
    so dont complain ..go buy a breathilizer if you dont thinks so

  69. john
    June 8, 2011

    Celtickane, could you please provide a reference for your comments here.

  70. JuggFuckler
    June 25, 2011

    I was thinking about skipping a PBT this morning but I used this calculator and it said I’d be good to go and blow a .000 so I went and I did indeed blow negative. A skipped PBT would’ve been pretty bad so I’m glad I used this calculator to ease my mind.

  71. Jazzy J
    July 5, 2011

    Can you give me an exact BAC

    based on: 193Lbs., Im in very good shape (work out 4-5 days a week), I drink typicly on the weekends around 4-6 beers, Male.

    Consumption = 2 Blue Moons (bottles) & 10 Bud Lights (keg beer/12OZ) Time = First beer at 3pm / Last beer at 8:30pm. Had my blood drawn at 2:15 AM. (11 hours from the first beer/ 4 1/2 from my last beer)

    Thanks for your help.

  72. Duncan
    September 2, 2011

    A couple of days ago I was drinking and kept a tally of how much alcohol of what % I drank. Today, out of curiosity I calculated the amount of actual alcohol I consumed(ml*%alcohol.)
    I was wondering if this calculator would still be acurate if I used the adjusted amount and set the alchohol content to 100%. Or are there other problems with what I am trying to do?

  73. E Mugo
    September 9, 2011

    What constitutes or how do you classify a frequent drinker, heavy drinker or otherwise, are there any parameters?

  74. Elda
    September 14, 2011

    I need an explanation

    Condsider the following:
    180 lbs
    social drinker
    1 hr
    10 can(s) 12 oz

    I get BAC of 0.237%

    I then put in 10 again and I get 0.49%

    It looks like it remembered the first 10 and added the other 10 making 20 beers I think.

    Does it not clear previous results or am I not using this BAC correctly.

    Also, what is the Recalculate button for. I cannot seem to make it out.

    Is there somewhere that explains how to use this caclulator.


  75. Elda
    September 14, 2011


    I figured out I have to hit the “Clear Alcohol Total” button before I do a new caclulation.

    I still am not sure what the “Recalculate” Button is

  76. Mike
    November 26, 2011

    I understand that there is no good rule of thumb for determining alcohol metabolism. Having said that, can you provide any estimations or ‘rules’ that you used to determine the difference between Heavy Drinker and Frat Boy? It seems that many people feel that your calculator is quite accurate, but, as I do not have a breathilizer, it would be helpful to have some rough guidelines to determine where one might fall in the spectrum. Thanks!

  77. Jill
    November 27, 2011

    I feel the same as Mike. The calculator seems accurate and allows a high degree of precision but the one ‘squishy’ area is the Metabolic rate. For starters, as a female, ‘frat boy’ is still an option. But more seriously, I don’t understand what I’m selecting here. As the difference between “Frequent drinker” and “heavy drinker” is rather great, I feel like the calculator is compromised by a bit of fuzziness that could be cleared up. I drink a lot. Is that ‘heavy’ or ‘frequent’? I don’t know…

  78. Rich
    December 1, 2011

    I love this site and also enjoy drinking beer. I had a dui last year and have the interlock device in my car for 2 years. This calculator is perfect !!! It tells me what my limitations are and if followed one is sober at the end of the hours entered. Bravo Celtic Kane you are a friend for life. Thank Rich

  79. B-Wreck
    January 4, 2012

    You can use the “Recalculate” button if you change and of the parameters (length of time from first drink, tolerance, etc.)

  80. Marcos
    February 3, 2012

    This is good. Would you please release the source code if you’ve decided not to do a mobile app. There is a lot of garbage out there. Your BAC calculator is excellent. One must determine their metabolic rate on their own, but if they go with ‘social drinker’ the results will be in their favor in the majority of cases.

  81. celtickane
    February 3, 2012

    The source code is available as Javascript via “View Source” on the webpage, although I would like attribution if the source code is directly used for any mobile applications.

  82. John
    April 17, 2012

    I think if you are drinking a 5th a day, you can consider yourself a frat boy. A pint is still a heavy drinker. And so on.

  83. steve
    April 18, 2012

    what is the difference betweet a heavy drinker and a frat boy???????

  84. Me
    May 8, 2012


    The “Metabolic rate” selection has an impact on how long the effects will last (i.e. the ‘x’ axis) and subsequently what your estimated BAC is based on how long you’ve been drinking. If you select “Cheap date”, your BAC calculation will remain much higher after 3hrs of drinking compared to a “Frat boy” because your body takes longer to break down the alcohol.

  85. Dale
    May 11, 2012

    Define how elapsed time is figured. Some calculators say its from the time you started drinking and others say it from the last drink you consumed? Which is it. Need clarity please.

  86. celtickane
    May 11, 2012

    Elapsed time is the time from your first drink, assuming your alcohol level doesn’t go below zero during the elapsed time

  87. DEECEE
    May 27, 2012

    You might be drink

  88. DEECEE
    May 27, 2012

    Ok, autocorrect foiled me. I might be drink. :)

  89. JJJMMM
    June 16, 2012

    Where did you find this information on elapsed time? There is nothing I can see on the website. I’m not in protest of your answer, just wondered where you got the info.

    I always assumed “elapsed time” was from the last drink you had. Both synarios would come out differently.

    Just asking….have a great day/evening!

  90. celtickane
    June 16, 2012

    Because I made the calculator =) Elapsed time is used to determine how much alcohol is eliminated. Roughly, the calculator adds up all of the alcohol consumed, determines the metabolic rate per hour (mg of alcohol eliminated per hour), then multiplies the metabolic rate by the elapsed time.

  91. aussie
    June 16, 2012

    awesome i hope it works i got done for dui i blew .110 then blew .103 26 mins later at the station the machine faulted so i had to get a blood test chugged down like 1.5 litre of water i weight 126 kg ruthly 280 lbs i drink alot i think im some where between frequent and heavey drinker lets hop the hour and 12 mins i had to get below 0.08

  92. Charles
    June 23, 2012

    Would be cool if you added the following to your calculator to make it even more accurate:

    Real life scenario:
    total elapsed time between first drink and blood test at the station: 5.5hrs
    first drinks: 4 glasses of wine in first two hours
    second drinks: 2 glasses of wine in third hour
    third drinks: 1 glass of wine in fourth hour
    no drinks for 1.5 hours

    calculating it this way gives you an even more accurate reading, yes? Perhaps the ‘advanced’ option on your calculator?

    Nice tool,

  93. celtickane
    June 25, 2012

    It actually won’t improve the accuracy. After 5.5 hours, your BAC will be the same whether you had 7 drinks at once or over a 5.5 hour time period. Alcohol has a zero-order elimination rate, so your body will continually eliminate the same amount of alcohol per hour regardless of your BAC. In your example, the calculator could be improved to report a BAC at specific times (eg, BAC after first 4 drinks, after 2 more glasses of wine, etc.) rather than reporting a BAC after a specific elapsed time.

  94. Steph
    June 25, 2012

    While the end result would be the same, the graph would not be linear. If you took charles’ suggestion, you would get a better idea of what your maximum bac was while you were drinking. Here it assumes that you drank everything at once giving you an innacurately high bac at the beginning of your time line.

  95. celtickane
    June 26, 2012

    Completely agreed — the graph would be non-linear. I’ll definitely consider the suggestion for a future update. Thanks!

  96. fateswebb
    July 5, 2012

    not entirely true, think of it this way… say you drank 6 drinks in 30 minutes, and the sipped one drink for 2 and a half hours, now compare that to
    you sipped one drink for 2 and a half hours and then drank 6 drinks in 30 minutes

    the second scenario you would have a much higher BAC… since your body didn’t have time to process the alcohol for several hours like the first scenario did…

  97. Azkyroth
    July 6, 2012

    I’m very much thankful to have FINALLY found a BAC calculator that lets you specify quantity and alcohol percentage rather than relying on “standard drinks” which assume “a beer” is like 3% ABV. The only improvement I’d suggest would be to allow people to enter “fl oz” as a quantity selection.

  98. balls deep
    July 7, 2012

    All good points. But take in consideration eating while drinking also tamper’ s with your BAC level. Take red meat for example rich in protein . Will soak up a lot of the alcoholic drinks. You’uve. ingested if you add this to your BAC calculator .it would give you a much accurate reading.

  99. celtickane
    July 22, 2012

    The calculator assumes that you have a detectable (and “metabolizable”) BAC during the elapsed period. If your BAC falls below zero during the period and then you continue drinking, you would need to enter your elapsed time and BAC from the time of your first drink after your BAC was undetectable.

    Similarly, you couldn’t have a drink on Sunday, wait two days, have five drinks, and try to type in six drinks into the calculator over an elapsed period of three days.

  100. celtickane
    July 22, 2012

    Agreed that food will alter the absorption of alcohol. Unfortunately, to my knowledge, it isn’t possible to accurately adjust for food.

  101. yep
    August 31, 2012

    This calculator seems to be within .02 bac when compared to a good breathalyzer. And when you consider that that a breathalyzer has about the same variance, not bad. But as stated, I would not 100% rely on this but it gives a good approximation.

  102. misterjiggley
    October 5, 2012

    Is it possible to enter a starting BAC into this calculator?

  103. Arguile
    October 31, 2012

    Did you use MATLAB to create this calculator? If you did, can you get me the code or the formulas?
    Thank you!

  104. celtickane
    November 2, 2012

    Sorry — no MATLAB here. The calculator is written in Javascript

  105. Chris
    November 2, 2012

    Perhaps it was you, maybe not, but as of 11-2-2012 there is the “fl oz” option

  106. celtickane
    November 3, 2012

    Still available — look for “ounce(s)”

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