hair colour calculator

How this hair colour calculator works

This calculator gives you a quick planning estimate before you mix your colour bowl. It uses six core inputs: your current level, your target level, gray percentage, hair length, density, and chosen mix ratio. From those, it estimates:

• Recommended developer volume (10, 20, 30, or 40 vol)
• Total amount of product needed for your hair amount
• How much colour cream and developer to use
• A suggested gray coverage blend using natural + target shade

It is especially useful for home users who want cleaner planning and less waste. You can adjust one variable at a time and see how your formula changes.

What “level” means in hair colouring

Hair level is the depth of colour from dark to light:

• Levels 1–3: very dark (black to dark brown)
• Levels 4–6: medium depths (brown to dark blonde)
• Levels 7–10: lighter blonde range

If your target level is higher than your current level, you are trying to lift (lighten). If your target is lower, you are depositing (darkening).

Developer guide (simple rule of thumb)

10 Volume

Best for deposit-only services, glossing, toning at same depth, and minimal lift. Often used for refreshing faded colour.

20 Volume

The common choice for standard permanent colour and basic gray coverage. Good for around 1–2 levels of lift depending on hair condition and brand.

30 Volume

Used when more lift is needed (typically around 3 levels). Can be drying on fragile hair, so condition and porosity matter.

40 Volume

Reserved for high-lift scenarios. This is strong and not ideal for all situations, especially compromised hair or scalp applications. If the calculator suggests 40 volume, proceed cautiously and follow professional guidance.

Gray coverage strategy built into the tool

Gray hair can resist colour, so many formulas blend a natural base (“N” series) with the desired fashion tone. The calculator estimates a practical split:

• 0–24% gray: 100% target shade
• 25–49% gray: 75% target + 25% natural
• 50–74% gray: 50% target + 50% natural
• 75–100% gray: 25% target + 75% natural

This gives better anchoring while still keeping your tone direction.

Mix ratio and quantity planning

Not every formula uses the same ratio. Some permanent colours use 1:1, many demi formulas use around 1:1.5, and high-lift formulas may call for 1:2. The calculator converts your ratio into real numbers so you can measure quickly.

It also scales quantity by length and density, which helps avoid under-mixing. Running out mid-application can create uneven saturation, patchy lift, and unnecessary stress.

Best practices before you colour

• Do a patch test 48 hours before colour service.
• Do a strand test to check timing, lift, and tone.
• Clarify heavy buildup before colouring.
• Avoid intense heat styling right before chemical services.
• Use a post-colour conditioner to close and smooth the cuticle.

Important limitations

No calculator can fully account for porosity, previous box dye, metallic salts, henna layers, hard water buildup, heat damage, or curl pattern variability. Think of this as a planning assistant, not a guaranteed final formula.

If your hair has significant banding, prior bleach overlap, or major correction goals, a professional colourist is the safest route.

Quick FAQ

Can this calculator replace a professional consultation?

No. It helps estimate formula math, but a trained colorist assesses chemistry, history, scalp safety, and corrective pathways.

Will the suggested developer always work?

Not always. Brand chemistry differs, and hair condition changes results. Always verify against your product instructions.

Why did my result suggest more natural base for gray?

Natural series provides stronger background support for resistant white/gray fibers. More gray usually requires more natural in the mix.

How often should I recolour?

Most root touch-ups happen every 4 to 8 weeks, depending on growth speed, contrast level, and gray percentage.