Online Tool Store
Hair Developer Calculator
Estimate developer-to-color ratios and processing times for at-home or salon hair color application based on target lift.
This works right here on your device — nothing gets sent out.
General guidance only. Always follow your color or bleach manufacturer's mixing instructions and do a patch test 48 hours before use.
How it works
- Enter how much color or bleach you are mixing and pick a unit (grams, milliliters, or ounces).
- Choose a mixing ratio — 1:1, 1:1.5, 1:2, or a custom color-to-developer ratio.
- Pick your developer strength (10, 20, 30, or 40 volume) to see its peroxide percentage and typical lift.
- Read off how much developer to add and the total amount of mixture.
The formula
Developer amount is the color amount multiplied by the developer side of the ratio. Developer volume converts to hydrogen peroxide percentage by multiplying by 0.3.
Developer = Color × (developer parts ÷ color parts) Total mixture = Color + Developer Peroxide % = Volume × 0.3
Example: 60 g of color at 1:1.5 needs 60 × 1.5 = 90 g of developer, for 150 g total. 20 volume is 6% hydrogen peroxide. Ratios differ by brand, so always check your product's instructions.
FAQ
What do 10, 20, 30, and 40 volume developer mean?
Volume describes peroxide strength: 10 volume is 3%, 20 volume is 6%, 30 volume is 9%, and 40 volume is 12% hydrogen peroxide. Higher volume lifts more but is harsher on hair and scalp.
What is the standard developer to color ratio?
Many permanent colors mix 1:1 and many lighteners or high-lift colors use 1:2, but it varies by brand and product. Follow the manufacturer's instructions and use this calculator to scale the amounts.
Which developer volume should I use?
As a general guide, 10 volume is for toning or depositing color, 20 for standard color and gray coverage, 30 for lightening two to three levels, and 40 for maximum lift. When unsure, use the lower volume.
Does this tell me how long to leave color on?
No. Processing time depends on your hair, the product, and the result you want, so use the time printed on your product's instructions and check strand progress.
Can I use grams, milliliters, or ounces?
Yes. The ratio is unit-agnostic, so the developer amount comes out in whichever unit you choose. Just measure both parts in the same unit.
Is my data sent anywhere?
No. Everything is calculated in your browser and nothing is uploaded.
How we compare
| Feature | Online Tool Store | MiniWebtool | Calculator Academy | Sage Calculator |
|---|---|---|---|---|
| Preset 1:1, 1:1.5, and 1:2 ratios plus custom | ✓ | Preset ratios | Manual ratio entry | Preset ratios |
| Grams, milliliters, or ounces | ✓ | ✓ | ✓ | ✓ |
| Volume to peroxide percentage and typical lift | ✓ | Not shown | Not shown | Not shown |
| Instant results as you type, no ads, no sign-up | ✓ | Calculate button | Calculate button | Calculate button |
All four tools do the core color-to-developer math. This one also shows what each developer strength means, updating instantly, without a sign-up.