Alcohol strength converter
Convert between ABV, US proof and the old British proof scale, and see how many units are in a serving.
That's about the same as a spirit. A 330 ml serving holds about 13.2 alcohol units.
What it means
How strong is that?
Alcohol units use 10 ml of pure alcohol, the UK and EU standard, for a 330 ml serving. Guidance differs by country.
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Your strength in every unit
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Three things worth knowing
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US proof is double the ABV
40% ABV is 80 proof, 50% is 100 proof. The British scale is different again: 100° British is 57.15% ABV.
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Gunpowder proof
Sailors tested rum by soaking gunpowder in it. If it still lit, the spirit was "proved" — which happens at about 57% ABV, still called navy strength.
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By volume, not by weight
Alcohol is lighter than water, so 5% by volume is only about 4% by weight. Some countries label beer by weight, which makes it look weaker.
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Background
About alcohol strength
ABV is the percentage of the liquid that is pure alcohol by volume. US proof is simply twice that, so 40% ABV is 80 proof. The old British proof scale set 100° at 57.15% ABV.