Alcohol Proof Converter
Convert between ABV%, US proof (2× ABV), and UK proof (1.75× ABV) for spirits and beverages.
Enter any value to update all three alcohol strength units.
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Alcohol strength is measured differently around the world.
ABV (Alcohol by Volume) is the international standard. It represents the percentage of pure alcohol in a beverage.
US Proof is simply double the ABV.
- US Proof = ABV × 2
- A 40% ABV whiskey is 80 US proof
UK Proof (historical, largely discontinued) uses a different scale.
- UK Proof = ABV × 1.75
- A 40% ABV whiskey is 70 UK proof
- UK proof was based on the old “gunpowder test”
Common examples:
| Beverage | ABV | US Proof | UK Proof |
|---|---|---|---|
| Light beer | 4% | 8 | 7 |
| Wine | 13% | 26 | 22.75 |
| Vodka | 40% | 80 | 70 |
| Cask strength whiskey | 60% | 120 | 105 |
| Everclear | 95% | 190 | 166.25 |
The US proof system is simple: proof is just twice the alcohol by volume, so 40% ABV is 80 proof. The word has a colorful origin. Centuries ago British sailors “proved” their rum’s strength by soaking gunpowder in it and trying to light it; if it still burned, the spirit was “above proof.” That old British scale set 100 proof at about 57% ABV, which is why historical proof numbers don’t line up with modern US ones, a real trap when reading old recipes or vintage British labels.
Today most countries have dropped proof in favor of plain ABV, with the US the main holdout. Strength matters beyond taste: high-proof spirits are flammable, which is why overproof rum (75%+, 150+ proof) carries warnings and is the stuff used for flaming cocktails. ABV is the figure that travels everywhere, so when in doubt, convert proof back to ABV.
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This converter runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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