Why does my brewing software give a slightly different ABV?

This calculator uses the simplified formula (OG − FG) × 131.25, which is accurate for most beers up to about 10% ABV. Some tools use a more precise formula that corrects for the non-linear relationship between gravity and alcohol at higher gravities, which can differ by half a percent or more in strong beers and wines.

What if my final gravity is higher than expected?

A higher-than-expected FG usually means fermentation stalled or didn't fully attenuate — check your yeast health, fermentation temperature, and whether gravity has been stable over several days before recording it as final. Entering the reading as-is will simply show a lower resulting ABV.

ABV Calculator

Calculate alcohol by volume (ABV) for homebrewing from gravity readings.

How this is calculated

ABV% = (Original gravity − Final gravity) × 131.25

Assumptions used in this calculation

Simplified formula: Uses the standard simplified ABV formula (OG − FG) × 131.25, not the more precise gravity-corrected formula used for high-gravity brews above ~10% ABV.

About this calculator

The ABV calculator finds the alcohol by volume percentage of a homebrewed beer or wine from the original and final specific gravity readings.

Worked example

OG 1.050, FG 1.010

Result: 5.25% ABV

Was this helpful?

Frequently asked questions

Blood Alcohol Content (BAC) Calculator

Estimate blood alcohol content from drinks consumed, body weight and time elapsed.

ABV Calculator

About this calculator

Frequently asked questions

Why does my brewing software give a slightly different ABV?

What if my final gravity is higher than expected?

Related calculators