Paint Mixture Ratio Calculator

How Paint Ratio Mixing Works

Four steps to a repeatable custom color.

Paint Mixture Formulas

Amount Per Color

Ratio 2:1 with 3 liters total: color one gets (2 ÷ 3) × 3 = 2 liters, color two gets (1 ÷ 3) × 3 = 1 liter.

Percentage of Each Color

In a 2:1:1 mix, the colors are 50%, 25%, and 25% of the batch.

Scaling a Known Ratio

2:1, 4:2, and 6:3 are identical colors at different batch sizes. Double all parts to double the batch.

Popular Paint Mix Ratios

Color Mixing Fundamentals

Start With the Lighter Color

Pour the lighter color first, then add the darker color gradually. A little dark pigment changes a light base dramatically — the reverse is not true. You can always darken; lightening wastes paint.

Mix the Full Batch at Once

Hand-mixed batches vary slightly. For large projects, professionals "box" paint — mixing all containers of a color together first — so walls show no visible bands between batches.

Test Dry, Not Wet

Wet paint looks lighter and glossier than the dried result. Brush your test mix onto a sample board, let it dry fully, and view it in the room's actual light before committing.

Keep Brands and Finishes Consistent

Mix within the same product line and sheen. Different chemistries can react poorly, and mixing flat with gloss gives an unpredictable in-between finish.

Avoid These Mixing Mistakes

• Eyeballing ratios — measure parts properly or the color cannot be reproduced.
• Mixing in the can — use a separate clean container; contaminated cans ruin leftover paint.
• Skipping the test patch — the number one cause of repaint regret.
• Forgetting to record the ratio — without it, touch-ups become a new guessing game.
• Mixing old and new paint — check that older paint has not spoiled (sour smell, lumps) before blending.

Color Theory Basics for Paint Mixing

Understanding how pigments interact takes the mystery out of custom colors and prevents muddy results.

Subtractive Mixing

Paint follows subtractive color mixing: each pigment absorbs (subtracts) some wavelengths and reflects the rest. Mixing adds absorptions together, which is why mixed paints always get darker and less saturated than their parents — you cannot mix a brighter color than your brightest ingredient.

The Muddy Color Trap

Mud happens when a mix absorbs too broadly across the spectrum. The classic cause is combining colors with opposing undertones — for example, a green-leaning blue with an orange-leaning red makes brown instead of purple. For clean secondary colors, choose primaries that lean toward each other on the color wheel.

Undertones Matter More Than Names

"Red" is not one color — it ranges from orange-red to blue-red. Two paints both labeled red can mix completely differently with the same blue. Test every new combination on a sample board; the undertone reveals itself in the mix, not on the label.

Tint, Tone, and Shade

• Tint = color + white (lighter, softer — pastels)
• Shade = color + black (darker, richer — be careful, black overwhelms fast)
• Tone = color + gray (muted, sophisticated — ideal for modern interiors)

Most custom wall colors are tints or tones rather than pure hues. Starting from white and adding color gives far more control than starting from a saturated color and trying to lighten it.

Sheen and Finish Guide

The same color looks different at different sheens — and mixing across sheens creates unpredictable results.

Rule: only mix paints of the same sheen. A flat-plus-gloss blend lands at an unrepeatable in-between sheen and may cure unevenly.

Estimating Paint Quantity

Before calculating your mix ratio, confirm the total volume:

• Measure walls: length by height for each wall, subtract about 20 sq ft per door and 15 sq ft per window.
• Coverage: one gallon covers 350-400 sq ft per coat on smooth primed walls; textured or porous surfaces need more.
• Two coats minimum for color changes — double the single-coat estimate.
• Add 10% for waste, touch-ups, and the paint left in rollers and trays.

A 12x12 room with 8-ft ceilings has about 384 sq ft of wall; two coats need roughly (384 / 375) x 2 x 1.1 = about 2.3 gallons — buy 3 to be safe, since running short mid-wall is worse than leftover paint.

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