Watercolour Dilution & Wash Ratio Calculator
Choose the wash strength you want and how much you need to mix, and get an approximate water-to-paint starting ratio based on commonly taught watercolour consistency guides.
Choose Your Wash
Suggested Starting Ratio
How to Use This Tool
Pick the wash strength you want to achieve and enter how much mixed wash you need in millilitres. The tool suggests an approximate starting ratio of water to paint, described using the classic "consistency" comparisons watercolour artists commonly use: water, milk, cream and honey.
The Four Consistencies
Many watercolour teachers describe wash strength using everyday liquids as a visual guide: a light, watery wash flows and behaves like water itself; a medium wash has the thin, milky consistency of skim milk; a strong wash is thicker and more opaque, like cream; and full-strength paint, barely diluted, moves like honey off the brush. This is a widely used teaching approximation rather than an exact measurement.
Why Ratios Are Approximate
Unlike a fixed baking recipe, there is no single universally correct water-to-paint ratio, because it depends on your specific pigment (some are naturally more staining or transparent than others), your paper's absorbency, your brush, and the effect you want. This tool gives sensible starting points based on commonly taught guidance, which you should adjust by testing on scrap paper.
Tips for Better Washes
Mix a little more than you think you will need, since running out of a wash mid-way through a large area can cause visible tide lines. Test your mixed wash on a scrap piece of the same paper before applying it to your painting, as the same mix can look different once it dries.
Frequently Asked Questions
What does this calculator do?
It suggests an approximate starting ratio of water to paint for a chosen wash strength (light, medium, strong or full strength), scaled to how much mixed wash you say you need.
What do "like water", "like milk", "like cream" and "like honey" mean?
These are common teaching comparisons watercolour artists use to describe wash consistency: light washes flow like water, medium washes are thin like milk, strong washes are thicker like cream, and full-strength paint moves like honey off the brush.
Are these ratios scientifically exact?
No. There is no single universally correct ratio, since it depends on your specific pigment, paper and brush. These are commonly taught, approximate starting points meant to be adjusted by testing.
Why does the tool ask how much wash I need?
So the suggested water and paint amounts scale to the actual quantity you plan to mix, rather than only giving you a percentage.
What units does this tool use?
Millilitres (mL), a common unit for measuring liquid paint mixes.
Should I always test my wash first?
Yes. It is good practice to test a mixed wash on a scrap piece of the same paper before applying it to your painting, since colours can look different once dry.
Does this work for all paint types?
This guidance is written specifically for watercolour. Other paint types such as acrylic or gouache behave differently when diluted.
Is this tool free to use?
Yes, this tool is completely free to use with no sign-up required.
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Explore Painting KitsThese ratios are general, commonly taught educational guidance, not precise scientific measurements. Real wash consistency depends on your specific pigment, paper, brush and technique. Always test on scrap paper before applying to a final piece.