Model Paint Mixing Ratio Calculator

How it works

total parts = paint parts + thinner parts · paint ml = total × paint parts ÷ total parts · thinner ml = total × thinner parts ÷ total parts · drops = ml × drops-per-ml

Getting a consistent finish from an airbrush or a hand-mixed colour depends on hitting the same ratio every time, whether you are thinning for spraying or blending two colours. The maths is a simple proportion: add the parts, then split the total volume between them in that proportion. Because most modellers work from dropper bottles rather than a graduated cylinder, the calculator also converts millilitres into drops — a typical bottle gives roughly 20 drops per millilitre, so a 2:1 thin becomes an easy "so many drops of paint, half as many of thinner" you can count into the cup.

Worked example

For a 2:1 paint-to-thinner mix at 10 ml total: total parts = 3, so paint = 10 × 2 ÷ 3 = 6.67 ml and thinner = 10 × 1 ÷ 3 = 3.33 ml. At 20 drops per ml that is about 133 drops of paint to 67 drops of thinner.

Frequently asked questions