ABV from Gravity Calculator
Works out how strong a finished homebrew is, from the hydrometer readings before and after fermentation.
Alcohol by volume
— % ABV
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Alcohol by weight, about — %
Apparent attenuation — %
Reading this —
The formula
ABV = (OG − FG) × 131.25 attenuation = (OG − FG) ÷ (OG − 1)
As yeast turns sugar into alcohol, the liquid becomes less dense, and the drop in gravity shows how much has been converted.
What to watch out for
Take the first reading once the wort or must is mixed and cooled, and the last once fermentation has finished. Priming sugar added at bottling raises the strength a little more, usually by a few tenths of 1% ABV.
Frequently Asked Questions
What is the ABV of a beer from 1.050 to 1.010?
5.25%, with 80% apparent attenuation.
What is the ABV of a wine from 1.090 to 0.995?
About 12.5%. Final gravity can read below 1.000 because alcohol is lighter than water.