Work out final gravity and abv instantly with clear inputs, formula shown and shareable results.
The standard approximation is ABV = (OG - FG) x 131.25, accurate to about 0.2% for beers below 1.070. Above that, the advanced formula 76.08(OG-FG)/(1.775-OG) x FG/0.794 is more reliable because the simple linear factor overstates alcohol in strong worts.
Simple ABV
ABV % = (OG - FG) x 131.25
Advanced ABV
ABV % = 76.08 x (OG - FG) / (1.775 - OG) x FG / 0.794
Declared alcohol content is legally regulated with defined tolerances. Verify by an approved method before labelling.
The linear factor assumes a fixed relationship between gravity drop and alcohol, which breaks down at high alcohol because ethanol's effect on density is not linear. Above 8% ABV use the advanced form.
Slightly. Priming sugar ferments to add roughly 0.2-0.4% ABV depending on the dose, which matters when declaring alcohol content on a label.