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Custom Paint Color Mixing Ratio Calculator

The calculator converts the target RGB color into proportions of primary paint colors—red, green and blue—and optionally black for dark tones. It first normalizes the RGB values to fractions of white and then solves a simple linear system that balances each channel with its corresponding base pigment. The resulting mixture ratios are scaled so that the total volume matches the user‑specified area, coverage rate, and waste margin.

Enter the desired red channel value (0–255) of the color to reproduce.
Enter the desired green channel value (0–255) of the color to reproduce.
Enter the desired blue channel value (0–255) of the color to reproduce.
Percent of paint you want to add as waste or safety margin, typically 5‑15 %.
Total surface area that needs painting.
How many square meters a liter of paint covers on your wall or surface.

What it is

The Custom Paint Color Mixing Ratio Calculator translates a target RGB value into real‑world amounts of base paint colors—red, green and blue pigments—and black for tonal depth. By normalizing the RGB channels to fractional contributions, it builds a simple linear system that balances each color channel with its corresponding primary pigment. The engine then scales these fractions so that the total volume exactly matches the area to be painted, the specified coverage rate of paint (in square meters per liter), and any waste or safety margin added by the user. This deterministic tool gives DIYers concrete quantities they can purchase, ensuring accurate shade reproduction without relying on store samples or guesswork.

How to use it

First enter the red, green, and blue integer values (0–255) that describe the color you wish to replicate. Specify how much area (in square meters) you will paint and what coverage a liter of your chosen paint provides. Set a waste percentage—typically 5‑15 %—to account for spillage or mistakes. Click calculate; the page displays the exact liters needed of each primary pigment and any black pigment required, rounded to three decimal places.

Worked example

1. Convert RGB values to fractions: r = 120/255 ≈ 0.4706, g = 150/255 ≈ 0.5882, b = 200/255 ≈ 0.7843. 2. Sum the weights = 0.4706+0.5882+0.7843 ≈ 1.8431. 3. Compute base paint volume for 10 m² at 12 m² per liter: 10/12 = 0.8333 L. 4. Add 10 % waste: 0.8333 × 1.10 ≈ 0.9167 L total. 5. Scale factor = total / weight sum ≈ 0.9167 ÷ 1.8431 ≈ 0.4973 L per unit weight. 6. Multiply each weight by the scale: red ≈ 0.4706×0.4973 = 0.234 L; green ≈ 0.292 L; blue ≈ 0.390 L. No black pigment is needed. 7. The calculator outputs these volumes, rounding to 0.234 L red, 0.293 L green, and 0.390 L blue.

Inputs

  • Target Red Value: 120
  • Target Green Value: 150
  • Target Blue Value: 200
  • Waste Margin %: 10
  • Area to Paint (m²): 10
  • Coverage (m² / L): 12

Result

  • Red Paint Volume (L): 0.234
  • Green Paint Volume (L): 0.293
  • Blue Paint Volume (L): 0.39
  • Black Paint Volume (L): 0

Frequently asked questions

Why can’t the tool give me a formula for white or yellow pigments?

The simple additive model used here assumes only primary red, green, and blue pigments drive the color balance. In real paint mixing, secondary shades like white or yellow are complex composites of many chromophores; modelling them would require an extensive pigment database beyond the scope of this deterministic calculator.

What if my paint has a different coverage rate?

Enter your own coverage (m² per liter) in the input. The calculator uses that figure to scale total volume, so it works with any brand or finish—latex, oil‑base, enamel, etc.—as long as you know its coverage.

Is this calculator accurate for glossy finishes?

Glossiness affects surface reflectance but not the pigment proportion needed for the desired RGB value; hence the color ratios remain valid. Only overall coverage changes, which you specify separately.

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