ABV Calculator
Calculate alcohol by volume (ABV) from original and final gravity readings.
Result
How ABV Is Calculated
Alcohol by volume (ABV) measures how much of a finished drink is pure alcohol, expressed as a percentage of the total volume. For home brewers and winemakers, it is estimated from two specific gravity readings taken with a hydrometer.
- ABV% = (OG − FG) × 131.25
- Apparent attenuation% = (OG − FG) / (OG − 1) × 100
Original and Final Gravity
- Original Gravity (OG): the density of the wort or must before fermentation, measured relative to water (1.000). More sugar means a higher reading, typically 1.030 to 1.100.
- Final Gravity (FG): the density after fermentation, once yeast has converted sugar into alcohol. It is lower than the OG, commonly 1.000 to 1.020.
- Apparent attenuation: the share of the original sugar the yeast fermented, a useful gauge of how dry the drink is.
Worked Example
Suppose a beer starts at an original gravity of 1.050 and finishes at a final gravity of 1.010:
- ABV% = (1.050 − 1.010) × 131.25
- ABV% = 0.040 × 131.25 = 5.25%
Note: This calculator uses the standard ABV estimate of (OG − FG) × 131.25, which is accurate for most beers up to roughly 6–7% ABV. Stronger brews and other formulas may give slightly different results. Always take hydrometer readings at the correct temperature for the most reliable estimate.