Calculator

Blend proof calculator

Enter what is going into the glass or bottle. The calculator returns the blended proof and each component's share, using the same volume-weighted math as Thief & Blend.

How it works

Blend proof is the volume-weighted average of the components: each volume multiplied by its proof, summed, divided by total volume. Two ounces at 90 proof and one ounce at 125 proof land at 101.7, not at the midpoint of 107.5, because there is twice as much of the softer whiskey. The math, fully explained.

Sanity checks

The result can never fall outside the range of the components. If it does, an input is wrong. Adding water (proof 0) is the only way to get below every whiskey in the blend.

Working in ABV

If your bottles say ABV, double the number to get proof, or use the converter. Never mix the two units in one calculation.