Calculate alcohol by volume from original gravity (OG) and final gravity (FG). Supports Specific Gravity and Plato, standard and alternate formulas, apparent attenuation, and calories per 12 oz.
Take OG before pitching yeast. Take FG after fermentation finishes, before priming sugar.
Use Standard for most beers. Alternate (Hall) is better for high-gravity batches above ~1.070 OG.
Hydrometer readings should be temperature-corrected. If you used a refractometer during fermentation, convert Brix/°P carefully — alcohol skews refractometer readings.
Best for everyday beer strengths. Widely used by homebrewers:
ABV = (OG − FG) × 131.25Example: OG 1.050 and FG 1.010 → (1.050 − 1.010) × 131.25 = 5.25% ABV.
More accurate for high-gravity beers (Dr. Michael Hall / Zymurgy):
ABV = (76.08 × (OG − FG) / (1.775 − OG)) × (FG / 0.794)Same example yields about 5.34% ABV with the alternate equation.
Apparent attenuation estimates how much sugar yeast consumed: (1 − FG°P / OG°P) × 100. With OG 1.050 and FG 1.010 that is about 79%.
Calories per 12 oz follow the ASBC Beer-33 method (real extract + alcohol by weight). The same sample returns about 163.7 calories per 12 oz bottle. Calorie math is independent of which ABV equation you select.
Density of wort before fermentation — a measure of available sugars. Higher OG usually means higher potential ABV.
Density after fermentation. Lower FG means a drier beer; higher FG means more residual sweetness and body.
Specific gravity compares density to water (e.g. 1.050). Degrees Plato (°P) express dissolved solids as a percentage by weight. This calculator converts between both.
Percent of the finished beer that is ethanol by volume — the number on most beer labels.
The standard formula is ABV = (OG − FG) × 131.25, where OG and FG are specific gravity readings. For higher-gravity beers, the alternate Hall formula is usually more accurate.
Most session beers are about 3–5% ABV, standard ales and lagers 4–6%, and stronger styles like IPA, Belgian tripels, or imperial stouts often range from 7–12%+ ABV.
Use whichever unit your hydrometer or refractometer reports. CalculatorMint converts between SG and °Plato automatically and shows both in the results.
Use the alternate (Hall) equation for high-gravity beers, especially above roughly 1.070 OG / 8% ABV. For everyday homebrew strengths, the standard formula is fine.
Want a deeper walkthrough? Read How to calculate beer ABV from OG and FG.