ABV from Brix Calculator

About this calculator

Brix measures the sugar content of a liquid as a percentage by weight, and winemakers and cider or mead makers track it before and after fermentation because yeast converts that sugar into alcohol in a roughly predictable ratio. Since a hydrometer or refractometer reading in Brix isn't directly usable in the standard ABV formulas (which are built around specific gravity), the calculation first converts original and final Brix into specific gravity, then applies a formula such as (OG − FG) × 131.25 to estimate alcohol by volume.

Home winemakers and cidermakers who only own a refractometer (which reads Brix, not specific gravity directly) use this conversion to estimate their finished ABV without needing a second instrument, and it's also useful mid-fermentation as a way to track how far along the sugar-to-alcohol conversion is. Refractometer readings taken after fermentation starts need an additional correction for the presence of alcohol, which skews the raw reading, so results from this method are treated as an estimate rather than a lab-grade figure.

This calculator takes your original and final Brix readings and returns the estimated alcohol by volume of your finished batch.