Calculator

Whisky dilution calculator

Adding water lowers alcohol by volume (ABV) because the amount of pure alcohol remains essentially unchanged while total liquid volume increases. This calculator estimates the water required for a chosen target strength.

How the calculation works

The calculator uses the standard dilution relationship C1 × V1 = C2 × V2, where C is alcohol concentration and V is volume. For 30 ml at 58% ABV reduced to 46% ABV, the final volume is 30 × 58 ÷ 46, or about 37.8 ml. Subtracting the original 30 ml gives about 7.8 ml of added water.

What the result does not tell you

The calculation gives a volume estimate. It cannot predict whether you will prefer the whisky at that strength. Aroma and flavour perception depend on the whisky, serving temperature, glass, time in the glass and the person tasting it. Add water incrementally if you are exploring how a whisky changes.

Why we do not promise an exact number of drops

Drop size changes with the dropper, surface tension and technique. Millilitres provide a more defensible measurement. If you use a dropper, calibrate it against a known volume before treating a drop count as a measurement.