Calculate developer and combined amounts for permanent color, lightener, demi-permanent color, or a custom ratio. Enter the manufacturer’s specified ratio and choose its weight or volume measurement basis.

Enter the ratio specified for your permanent color.

Follow the product’s mixing, developer-strength, allergy-test and timing instructions. Ratio arithmetic alone does not establish safety.

Use the label’s basis; grams and mL are not interchangeable.

For a label ratio of 1:1.5, enter 1.5. No product ratio is assumed.

Related Calculators

Hair Dye Ratio Formula

The following formula is used to calculate the desired amount of dye or developer based on their ratios.

D = (V / Rd) × Rₕ

Variables:

  • D is the desired amount of dye
  • V is the desired amount of developer
  • R_d is the developer ratio
  • R_h is the dye ratio

To calculate dye from a known developer amount, divide developer by its ratio parts and multiply by dye parts. The widget works in the other direction: developer V = (D / R_h) × R_d. Use matching weight or volume units for the manufacturer’s specified basis.

What is a Hair Dye Ratio?

A hair dye ratio refers to the proportion of hair dye to developer that should be mixed together to achieve the desired hair color. The ratio and measurement basis are specified by the manufacturer and vary by product; a product category alone does not establish them. Follow the product’s developer-strength, allergy-test and processing instructions. Common ratios include 1:1, 1:1.5, and 1:2, where the first number represents the amount of dye and the second number represents the amount of developer. Mixing the correct ratio is crucial for achieving consistent and predictable results.

How to Calculate Hair Dye Ratio?

The following steps outline how to calculate the Hair Dye Ratio.

  1. First, determine the desired amount of dye (D).
  2. Next, determine the desired amount of developer (V).
  3. Next, determine the developer ratio (R_d).
  4. Next, determine the dye ratio (R_h).
  5. Finally, calculate developer using V = (D / R_h) * R_d, or use the displayed inverse formula to calculate dye from a known developer amount.
  6. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Desired amount of dye (D) = 50 ml

Desired amount of developer (V) = 75 ml

Developer ratio (R_d) = 1.5

Dye ratio (R_h) = 1