How many sessions does colour correction take?

It depends on the level change needed and hair condition. A 1-2 level change may take one session. Going from dark to blonde (4+ levels lighter) often requires 2-4 sessions spaced 4-6 weeks apart to protect hair integrity. Damaged hair needs more sessions with gentler processing.

What is colour filling and when is it needed?

Colour filling replaces missing underlying pigment when going darker. If you colour previously lightened hair directly with a dark shade, the result will look flat, ashy or green because the warm pigment has been removed. Filling first with copper, gold or red tones (depending on target level) ensures a natural, warm result.

How do I neutralise unwanted tones?

Use the opposite colour on the colour wheel. Blue cancels orange, violet cancels yellow, and green cancels red. Ash-based colours contain blue-green pigments that neutralise warmth. The amount of neutralising pigment needed depends on the intensity of the unwanted tone.

CutCalcs

Colour Correction Calculator — Steps & Product Estimates

Estimate the number of colour correction sessions, products and processing approach needed.

Current Hair Level

Select an option for current hair level

Target Hair Level

Select an option for target hair level

Unwanted Tone

Select an option for unwanted tone

Hair Condition

Select an option for hair condition

How We Calculate This

This calculator estimates the colour correction process based on the difference between your current and target levels, hair condition and the unwanted tones present.

How it works

Level difference determines the number of sessions
Hair condition multiplies the session count (damaged hair = more sessions)
Going lighter requires bleach; going darker requires colour filling
Unwanted tones are neutralised using complementary colours

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always perform a strand test before chemical services.