United KingdomTier 1
ABV to proof calculator
US proof is exactly twice ABV. Enter either value — the other updates live.
Free·No sign-up·Last checked 2026-08-27
Formula
Proof = ABV × 2ABV = Proof ÷ 2Worked example. 40% ABV × 2 = 80 proof. 100 proof ÷ 2 = 50% ABV.
Method
US proof only — UK proof was retired in 1980
Every UK spirits label now states ABV, so there's no reason to convert to the old UK proof scale. This calculator is for reading American labels, where proof is still standard and is defined as exactly twice ABV.
Questions
No. UK proof was a different scale (about 1.75× ABV) that was retired in 1980 in favour of ABV, which is what every UK label now carries. Proof survives mainly on American whiskey and bourbon labels, where it's exactly twice ABV — that's what this calculator converts.
Proof is a historical US and Canadian labelling convention, mostly seen on spirits. ABV is the internationally standard figure and the one required on UK and EU labels.