Homebrew ABV Calculator

Alcohol by Volume (ABV) is estimated by measuring the density of a liquid before and after fermentation. As yeast converts sugars to alcohol and CO₂, the density drops. The difference between the original gravity (OG) and final gravity (FG) indicates how much sugar was converted to alcohol.

Standard Formula

ABV = (OG − FG) × 131.25

This is the most common formula, derived from the relationship between specific gravity drop and ethanol production. It works well for beers and lower-alcohol beverages.

Alternate Formula

ABV = (76.08 × (OG − FG) / (1.775 − OG)) × (FG / 0.794)

This formula, adapted from brewing science, accounts for the nonlinear relationship between gravity and alcohol at higher concentrations. It is more accurate for strong beers, wines, and meads above ~8% ABV.

Other Calculations

• ABW (alcohol by weight) = ABV × 0.79336
• Apparent attenuation = (OG − FG) / (OG − 1) × 100%
• Plato = 259 − 259 / SG (approximate conversion)
• Calories estimated from alcohol and residual carbohydrate content per 12 oz serving

Brix / Plato

Brix and Plato are scales that measure sugar content by weight percentage. A refractometer reading of 12 °Brix means the liquid is 12% sugar by weight. This calculator converts Brix to specific gravity so you can use either input format. Note that refractometer readings after fermentation must be corrected for alcohol presence — this calculator applies the standard correction automatically.

Typical ABV Ranges

• 3 – 4% — Light lagers, session ales
• 4 – 6% — Pale ales, wheat beers, most lagers
• 6 – 8% — IPAs, stouts, Belgian ales
• 8 – 12% — Imperial stouts, barleywines, strong ales
• 10 – 15% — Wines, meads, ciders
• 15%+ — Fortified wines, high-gravity meads