Food & drink · Brewing
Beer ABV calculator.
Enter your original and final gravity to get alcohol by volume with both common formulas, or enter a target ABV to find the final gravity it needs.
Inputs
Alcohol by volume
Enter both gravity readings.
How to calculate ABV from gravity
The standard homebrewing formula is ABV = (OG − FG) × 131.25. An alternate formula, ABV = 76.08 × (OG − FG) ÷ (1.775 − OG) × (FG ÷ 0.794), is intended to be more accurate for stronger brews. Both come from the Brewer’s Friend and Homebrew Academy calculators. Homebrew Academy notes the simple formula may be less accurate at higher ABV, so the tool shows both.
Worked example. OG 1.050 and FG 1.010: (1.050 − 1.010) × 131.25 = 5.25%. The alternate formula gives 5.34%. A 355 mL serving at 5.25% is 1.09 Canadian or 1.05 US standard drinks. To land at 5% from an OG of 1.050 the FG would need to be 1.012.
The formulas depend on the sugar fermented, so they are commonly applied to cider, mead and wine too, but the sources cited here cover beer. Readings must be specific gravity (1.050 style), not Plato or Brix.
Frequently asked questions
How do you calculate ABV from OG and FG?
Subtract the final gravity from the original gravity and multiply by 131.25. For 1.050 and 1.010 that is 5.25%.
Which ABV formula is more accurate?
The alternate formula is intended for higher-gravity brews, where Homebrew Academy notes the simple one may be less accurate. In the example the two differ by 0.09 points.
What FG do I need for 5% ABV?
With an OG of 1.050 the FG needs to be about 1.012, from FG = OG minus ABV divided by 131.25.
Does this work for cider or wine?
They are commonly applied to cider, mead and wine because they use the sugar fermented, but the sources cited here cover beer only. Check your local rules on making alcohol at home.
Sources
Opened
- Brewer's Friend: ABV Calculator: Standard formula ABV = (OG - FG) x 131.25 and the alternate formula.
- Homebrew Academy: ABV Calculator: Gives both formulas, a worked example at 1.075 OG and 1.015 FG, and notes the simple formula may be less accurate for higher-ABV brews.
- Health Canada: Low-risk alcohol drinking guidelines: A Canadian standard drink is 17.05 mL or 13.45 g of pure alcohol.
- NIAAA: What is a standard drink?: A US standard drink contains 14 grams of pure alcohol.
- CCSA: Canada's Guidance on Alcohol and Health: Lists 2 standard drinks or less per week as the level where you are likely to avoid alcohol-related consequences, and says risk rises with each additional drink.
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Scope
Estimates from hydrometer readings, not a lab measurement. Drink responsibly. Canada’s Guidance on Alcohol and Health (CCSA) puts 2 standard drinks or less per week as the level where you are likely to avoid alcohol-related consequences, and says risk rises with each additional drink. Never drive after drinking, and follow your local rules on serving alcohol. This tool is arithmetic, not medical or legal advice.