Mix dye and developer in the correct ratio for a batch.
Boxed hair color must be mixed in a specific dye-to-developer ratio, which splits the total batch proportionally between the two components. Using the wrong ratio weakens or over-activates the color, so scaling the mix from parts keeps results predictable.
Hair Dye Mixing Ratio
Dye volume = total x dye parts / (dye parts + developer parts)
Dye volume = total x dye parts / (dye parts + developer parts) Boxed hair color must be mixed in a specific dye-to-developer ratio, which splits the total batch proportionally between the two components.
Using the wrong ratio weakens or over-activates the color, so scaling the mix from parts keeps results predictable.
This calculator takes 3 inputs: Dye parts, Developer parts, Total mixture volume. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.