ABV Calculator (Alcohol by Volume)

Written by Great Medico

Updated September 25, 2026 •2 min read

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A good food calculator should save time without hiding what it assumes. The ABV Calculator (Alcohol by Volume) is built to estimate ABV and related fermentation values from original extract, apparent extract, and batch volume. The result is most useful when the ingredient, unit, serving, or process choice on the page matches what you are actually preparing.

What this calculator does

The ABV Calculator (Alcohol by Volume) uses the fields on this page to estimate ABV and related fermentation values from original extract, apparent extract, and batch volume. Its primary output is labeled “Alcohol by volume” and is displayed in % ABV. Supporting readouts include Real extract (RE), ADF, RDF.

How to use it

Enter the known values in Original extract (OE), Apparent extract (AE), Total volume. Leave the value you want to solve from the relationship blank when the page supports reverse solving. Keep concentrations on the same percentage basis and quantities in the units shown; the calculator handles its supported unit conversion before applying the equation.

How the calculation works

From original extract (OE) and apparent extract (AE), the calculator derives apparent attenuation, real extract, real attenuation, alcohol by weight, then estimates ABV as ABW × 1.25. It also reports U.S./UK proof and alcohol volume for the entered batch size.

Example

With Original extract (OE) = 12, Apparent extract (AE) = 3, Total volume = 1 L, the calculator returns 4.67 % ABV for “Alcohol by volume.” The same run also shows Real extract (RE) = 4.75; ADF = 75%; RDF = 60.39%; ABW = 3.74%. Changing one input at a time makes it easy to see which assumption is driving the result.

How to interpret the result

For the ABV Calculator (Alcohol by Volume), read the result as a process-calculation target. Small changes in measurement can matter, so keep the original inputs with the result and use appropriate brewing, winemaking, or baking measurements when precision affects the finished product.

Limitations and notes

This is a fermentation estimate, not a laboratory assay or legally sufficient label measurement. Hydrometer/refractometer calibration, temperature correction, fermentation byproducts, and the meaning of extract scales can shift the true ABV.