Homebrew ABV Calculator
Alcohol by volume from original and final gravity.
Enter your values
ⓘ Live results
Results
- ABV (standard formula)
- 5.25%
- ABV (high-gravity formula)
- 5.34%
- Apparent attenuation
- 80%
Quick answer
ABV is calculated from the drop in specific gravity between the original and final readings during fermentation.
ABV% = (OG - FG) x 131.25
How to use the Homebrew ABV Calculator
- 1Take an original gravity (OG) reading before fermentation begins.
- 2Take a final gravity (FG) reading once fermentation has finished (stable reading over a few days).
- 3The standard formula works well for most beers; use the high-gravity formula for strong beers/meads above ~1.070 OG.
Worked example
Using the values the calculator loads with:
Inputs
- Original gravity1.050
- Final gravity1.010
Results
- ABV (standard formula)5.25%
- ABV (high-gravity formula)5.34%
- Apparent attenuation80%
Frequently asked questions
Why two ABV formulas?
The standard linear formula loses accuracy at higher gravities, so a more precise formula is used for strong brews.
What if my FG reading is still dropping?
Wait until it's stable for 2-3 consecutive days before taking your final reading to avoid bottling too early.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.