Standard Drink Calculator
Estimate your standard drink with our free addiction medicine calculator. See reference ranges, risk factors, and next-step guidance.
Reviewed by Rahul Singh, Health & Wellness Specialist
Formula
Standard Drinks = (Volume(ml) x ABV/100 x 0.789) / 14g
Pure alcohol in milliliters equals volume times ABV percentage. Multiply by 0.789 (alcohol density in g/ml) to get grams of pure alcohol, then divide by 14 grams (the US standard drink definition). BAC is estimated using the Widmark formula accounting for body weight, gender, and time elapsed.
Worked Examples
Example 1: Beer Night Calculation
Problem:A 75 kg male drinks 3 bottles of craft beer (355 ml each, 7% ABV) over 3 hours. Calculate standard drinks and estimated BAC.
Solution:Pure alcohol per bottle = 355 x 0.07 = 24.85 ml\nAlcohol grams per bottle = 24.85 x 0.789 = 19.61 g\nStandard drinks per bottle (US) = 19.61 / 14 = 1.40\nTotal standard drinks = 1.40 x 3 = 4.20\nTotal alcohol = 19.61 x 3 = 58.83 g\nBAC = (58.83 / (75,000 x 0.68)) x 100 - (0.015 x 3)\nBAC = 0.1154 - 0.045 = 0.070%
Result:4.20 standard drinks | BAC: 0.070% | Reduced coordination
Example 2: Wine with Dinner
Problem:A 60 kg female has 2 glasses of wine (150 ml each, 13% ABV) over 2 hours with food. Calculate standard drinks and BAC.
Solution:Pure alcohol per glass = 150 x 0.13 = 19.5 ml\nAlcohol grams per glass = 19.5 x 0.789 = 15.39 g\nStandard drinks per glass (US) = 15.39 / 14 = 1.10\nTotal standard drinks = 1.10 x 2 = 2.20\nTotal alcohol = 15.39 x 2 = 30.78 g\nBAC = (30.78 / (60,000 x 0.55)) x 100 - (0.015 x 2)\nBAC = 0.0933 - 0.030 = 0.063%
Result:2.20 standard drinks | BAC: 0.063% | Reduced coordination
Frequently Asked Questions
What is a standard drink and how is it defined?
A standard drink is a unit of measurement that represents a specific amount of pure alcohol, used to track consumption and assess health risks. The definition varies by country: in the United States, one standard drink contains 14 grams (0.6 fluid ounces) of pure alcohol. In the United Kingdom, one unit contains 8 grams. In Australia, one standard drink contains 10 grams. In Canada and most European countries, it ranges from 10-14 grams. These amounts translate to approximately: one 12-ounce beer at 5% ABV, one 5-ounce glass of wine at 12% ABV, or one 1.5-ounce shot of distilled spirits at 40% ABV for the US standard. Understanding standard drinks helps individuals monitor their alcohol intake relative to recommended guidelines.
References
Reviewed by Rahul Singh, Health & Wellness Specialist · Editorial policy