Hair Dye Developer Ratio
Calculator
Results
- Developer needed (g)
- 90
- Total mix (g)
- 150
- Colour as a share of the mix (%)
- 40
- Developer hydrogen peroxide (%)
- 5.555555
Beauty and personal care results
| Developer needed (g) | 90 |
| Total mix (g) | 150 |
| Colour as a share of the mix (%) | 40 |
| Developer hydrogen peroxide (%) | 5.555555 |
formula-map diagram
- Developer needed (g)
- 90
- Total mix (g)
- 150
- Colour as a share of the mix (%)
- 40
- Developer hydrogen peroxide (%)
- 5.555555
Beauty and personal care relationship
Formula
developer = colour × ratio= 90
Note
This is a simplified model: it applies the mixing ratio, dilution, application rate, growth rate or price you enter to plain arithmetic. Mixing figures use the ratio on your own product's label, because developer, powder and colour ratios differ from brand to brand. Dilutions use C1 x V1 = C2 x V2 and the standard conversion of 20 drops per millilitre; real droppers vary with the oil's viscosity and the dropper itself. Sunscreen amounts use the Du Bois body surface area formula with the application rate you enter, and the SPF figure uses the textbook approximation protection time = SPF x unprotected burn time, which is a simplification: sweat, water, towelling, UV index, altitude, reflection and your own skin all shorten it in practice. Hair, nail and hair-removal timings assume a constant linear growth rate, which varies by person, body area, age, season and health. Costs ignore taxes, sales and waste. Always patch test a new product on a small area first and follow the product label and any professional instructions. This is not dermatological, cosmetic or medical advice; see a dermatologist or a qualified professional for anything affecting your skin, scalp or health.
More in Beauty and personal care
See all →Frequently asked questions
What does the developer ratio actually control?+
The ratio of hair colour to developer determines how much hydrogen peroxide is available to open the hair cuticle and activate the dye's oxidation process; a standard ratio (commonly 1:1 or 1:1.5 depending on the product line) is set by the manufacturer to balance color deposit against the volume of developer used.
Why do different techniques call for different ratios, like 1:2?+
Higher developer ratios (such as 1:2) dilute the color slightly while providing more oxidizing power and working time, which is useful for lightening services or resistant grey hair, whereas standard toning or deposit-only color typically uses a lower ratio to keep more pigment concentration relative to developer.
Does using more developer than recommended lighten hair faster?+
Not proportionally and not safely: exceeding the manufacturer's recommended ratio does not reliably speed up lightening, but it does dilute the color pigment and increases the risk of scalp irritation and hair damage, so ratios should not be adjusted beyond the product's documented range.
How do I scale the ratio for a larger or smaller amount of hair colour?+
The ratio stays fixed regardless of total volume; you simply scale both parts up or down together, so if a 1:1.5 ratio calls for 30g of colour and 45g of developer, doubling to 60g of colour still requires the same 1:1.5 ratio, meaning 90g of developer.
Why does the same ratio sometimes produce different results on different hair?+
Porosity, existing color, and grey coverage percentage all affect how much pigment and developer the hair actually absorbs, so identical ratios can process differently on virgin hair versus previously colored or highly porous hair, even though the mixing math is the same.