Free tool
ABV to Proof Converter
In the US, proof is exactly twice the alcohol by volume (ABV). Enter ABV or proof to convert between them, with an approximate alcohol-by-weight figure.
The formula
proof = ABV x 2 | ABV = proof / 2 | ABW ~= ABV / 1.267
US proof definition (27 CFR 30.11 measures spirits in degrees of proof). This tool uses the same calculation as the Spirit Sight platform. It is general information, not tax or legal advice.
How do you convert ABV to proof?
In the US, multiply ABV by 2. 40% ABV is 80 proof.
How do you convert proof to ABV?
Divide the proof by 2. 100 proof is 50% ABV.
What is alcohol by weight (ABW)?
A weight-based measure, roughly ABV divided by 1.267. It is lower than ABV because alcohol is less dense than water.
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