Watercolor Dilution Calculator
The watercolor dilution calculator helps artists achieve consistent, repeatable paint-to-water ratios for washes, glazes, and layered painting. Watercolor painting involves dissolving pigment in water to varying degrees of dilution, and knowing your ratio allows you to reproduce a specific shade or transparency reliably. Enter the amount of paint you are starting with and your desired dilution ratio (paint-to-water), and the calculator tells you how much water to add and the total wash volume. This is especially helpful when preparing large wash batches for graduated skies, flat colour areas, or consistent background washes.
Dilution formula
Water (ml) = Paint (ml) x Water ratio
Total wash (ml) = Paint + Water
Paint concentration (%) = Paint / Total wash x 100
Example: 2 ml paint, ratio 1:10
Water = 2 x 10 = 20 ml, Total = 22 ml, Concentration = 9.09%
Frequently asked questions
What paint-to-water ratio gives a light watercolor wash?
A light wash (transparent, barely visible colour) typically uses a ratio of about 1 part paint to 10 to 20 parts water. A mid-tone wash uses 1:5 to 1:10. A heavy wash closer to full pigment strength uses 1:1 to 1:3. These are starting points; the exact ratio depends on the pigment's transparency rating and the paper.
How do I maintain consistent dilution across a painting session?
Pre-mix a consistent dilution in a small mixing cup or palette well using measured amounts of paint and water. Keep a note of your ratios. When you need to remix, use the same measurements. This calculator helps you scale a known ratio up or down for larger or smaller quantities.
Does watercolor paper affect dilution results?
Yes. More absorbent paper (rough or cold-press) absorbs more water and pigment faster, making washes appear lighter and spreading more. Hot-press (smooth) paper holds washes longer and can look more intense. Adjust dilution based on your paper as well as the pigment.
What is the difference between transparent and opaque watercolor pigments?
Transparent pigments (such as Phthalo Blue, Quinacridone Rose) allow light to pass through them, creating luminous glazes. Opaque pigments (such as Cerulean Blue, Cadmium Yellow) block light more and can create flat, chalky washes when heavily diluted. Transparency ratings are printed on professional watercolor tubes.
Can I use this calculator for gouache and liquid watercolors?
Yes. The dilution ratio formula applies to any water-based paint medium. Gouache is more opaque and typically used with 1:1 to 1:3 ratios for painting, or more water for transparent glazes. Liquid watercolors are already liquid, so adjust your ratio based on the desired intensity.
Sources
- National Gallery of Art: NGA - Watercolor Techniques and Materials.
- Smithsonian American Art Museum: Watercolor in American Art.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.