Alcohol Dilution Calculator

This page works out how much water to add to bring a spirit down to a target strength, and how strong two liquids come out when you blend them. It does the arithmetic by mass rather than by volume, because ethanol and water do not add up: a litre of each makes about 1.93 litres, not two, so subtracting the volumes gives the wrong amount of water. You get the water to add, the finished volume and strength, the figure the naive subtraction would have produced, and what that figure would actually have left you with. Everything is at 20 C, and the arithmetic assumes ethanol and water with nothing else dissolved in them.

Calculator Type

Volume Unit

Enter what you have and what you want. You get the water to add, the finished volume, and the figure the naive subtraction would have given you instead.

Volume You Have (mL) *

Strength You Have (% ABV) *

Alcohol by volume at 20 C. US proof is twice this number.

Strength You Want (% ABV) *

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