Free tool
ABV to Proof Converter
In the US, proof is exactly twice the alcohol by volume (ABV). Enter an ABV to convert to proof, read the reverse to go from proof to percent alcohol, and see an approximate alcohol-by-weight figure. This liquor proof calculator uses the same audited math as Spirit Sight.
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; 45% ABV is 90 proof.
How do you convert proof to ABV?
Divide the proof by 2 to get percent alcohol. 100 proof is 50% ABV; 80 proof is 40% 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, so the same volume percentage is a smaller weight percentage.
See your distillery in Spirit Sight
Book a walkthrough with our team. We’ll show your operation - barrels, TTB, and the books - in one place.
Schedule a Demo