Pricing Blog Formulas Tools About Download
ES | EN
Free tool

Hair color longevity calculator

Select color type, porosity, wash frequency and care routine. Get the estimated duration in weeks and tips to maximize it.

This calculator estimates.
Blendsor formulates with precision.

With the products you use, the client's history, and a complete diagnosis. Free.

Download on App Store Download on the App Store Get it on Google Play

Hair color longevity guide for professionals

Why color type changes everything

Permanent color penetrates the cortex and modifies melanin, which is why it lasts longer. Semi-permanent stays in the cuticle and direct dyes adhere to the surface. The deeper the pigment penetration, the longer the duration. But cuticle condition also matters: damaged hair with an open cuticle lets pigment in fast and releases it just as fast.

The five factors that shorten color life the most

In order of impact: (1) high porosity, which lets pigment escape; (2) frequent washing with sulfates, which strips color with every wash; (3) heat without thermal protection, which opens the cuticle; (4) hard water with minerals, which oxidizes pigment; and (5) direct sun exposure, which breaks color bonds. Controlling these five factors can double color longevity.

How to maximize color longevity

The most effective combination: sulfate-free or color-specific shampoo, washing every 2-3 days, filtered water or biweekly chelating treatment, thermal protection whenever using dryer or flat iron, and hair sunscreen in summer. Additionally, a cuticle-sealing treatment (acid, keratin) immediately after coloring can extend color life by up to 30%.

We answer your questions

Frequently Asked Questions

Everything you need to know before getting started

Permanent hair color lasts 6 to 8 weeks as a baseline, but actual duration depends on porosity, wash frequency, water type and care routine. Low-porosity hair washed every 3 days with sulfate-free shampoo can maintain color for over 10 weeks.
Semi-permanent dyes deposit pigment on the cuticle surface without penetrating the cortex. Each wash removes a layer of pigment. With daily washing and hard water, semi-permanent color can fade in under 2 weeks.
Yes. Hard water minerals (calcium, magnesium, iron) deposit on the cuticle and accelerate pigment oxidation. The result is dull color that tends to shift brassy or greenish. A shower filter or chelating treatment every 2-3 weeks reduces the impact.
Sulfates (SLS, SLES) are harsh detergents that strip pigment with every wash. A sulfate-free or color-specific shampoo can extend color life by 10-20% because it cleans without excessively opening the cuticle.
It is the most important factor alongside color type. High-porosity hair absorbs pigment quickly but releases it just as fast. Low-porosity hair takes longer to absorb but retains better. This is why a porosity assessment before coloring is key to adjusting the formula.
UV radiation breaks the chemical bonds of pigment (both natural and artificial). Intense sun exposure can reduce color longevity by up to 20%. Hair sunscreens with UV filters and hats are the most effective prevention.
The calculator estimates color longevity based on 7 general factors. Blendsor analyzes over 70 variables (brand, complete history, porosity, local water, care routine) and generates an optimized formula so color lasts as long as possible with the products used in the salon.

Have more questions?

Email us at hello@blendsor.com