Beer ABV Calculator
Calculate the alcohol by volume (ABV) of homebrewed beer from the original and final gravity readings.
ABV
5.25 %
How to Calculate Beer ABV
Formula
ABV = (OG - FG) x 131.25
This is the standard homebrewing formula. OG (original gravity) is measured before fermentation, and FG (final gravity) is measured after fermentation is complete.
Apparent Attenuation
AA = (OG - FG) / (OG - 1) x 100%
Attenuation measures what percentage of the available sugars were fermented. Most beer yeasts achieve 65-80% apparent attenuation.
Taking Gravity Readings
Use a hydrometer or refractometer. Hydrometers are calibrated to 60°F; adjust for temperature differences. Refractometer readings after fermentation need a correction factor because alcohol changes the refraction.
Example Calculation
A pale ale with OG 1.050 and FG 1.010.
- 01ABV = (1.050 - 1.010) x 131.25 = 5.25%
- 02Attenuation = (1.050 - 1.010) / (1.050 - 1) x 100 = 80%
- 03This is a well-attenuated beer at a standard strength.
Frequently Asked Questions
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