Wash Size Calculator — Watercolour Wash Volume

Always mix more than you think you need — running out mid-wash creates a hard edge that is nearly impossible to fix. By default this calculator adds a 50% safety margin (adjustable under Advanced Options). For large or unbroken washes, err on the side of too much. The coverage figures are practical studio estimates, not exact constants — actual paint use varies with brush, paper sizing and how wet you work.

A flat wash has even colour across the area. A graded wash transitions from strong to light (or vice versa). A variegated wash blends multiple colours. Graded and variegated washes use slightly more paint due to overlapping strokes.

Put water in a clean container first. Add concentrated paint gradually, stirring thoroughly. Test on scrap paper. The colour should be slightly darker than desired — watercolour lightens by 20-30% when dry.

Light washes (transparent tints) use about 5% paint to water. Medium washes (standard) use 10%. Strong washes (deep colour) use 20%. The more transparent the wash, the more water you need.

Yes — store in a sealed container and it will keep for days. The pigment may settle — stir before reuse. Diluted washes are also useful for tinting subsequent layers or mixing new colours.