Hair Color Developer Calculator
Work out which developer volume to use for the lift you are trying to achieve. Pick your natural level and your target level, and the page returns the peroxide strength, the processing window and the mixing quantities for a full application.
One Number Decides the Developer
The developer does the lifting; the colour only deposits. Its strength is what determines how many levels of natural pigment can be removed, and that is why the entire calculation reduces to a single subtraction: target level minus starting level. Everything else the page reports follows from that difference.
- Hair levels run from 1 for black through to 10 for the lightest blonde, and the page offers all ten for both the starting and the target colour.
- The lift is the target level minus the starting level. A move from level 4 to level 8 is a lift of four levels.
- The developer strength is chosen from the size of that lift: 10 volume for depositing and toning, 20 volume for one to two levels, 30 volume for two to three, and 40 volume beyond that.
- The processing window comes from the same table, and it is a range rather than a fixed time because the rate of lift depends on the hair itself as well as on the developer.
Choosing the Levels and Reading the Output
- Identify your natural level honestly. The chart on the selector runs from 1 Black to 10 Lightest Blonde, and most people overestimate their level by one or two steps, which leads them to choose a developer that is too weak.
- Choose the target level. If you are matching a box colour, the shade number usually starts with the level, so a 6.34 is a level 6 target.
- Read the lift, which is reported as the number of levels required and never displayed below zero. Colouring darker than your natural level needs no lift at all.
- Read the developer recommendation. It is given as a volume and as a percentage, because the two conventions are both in use in different markets.
- Check the processing time for that developer and set a timer. Over-processing lightens beyond the target and cannot be reversed.
- Use the mixing quantities for a full application: 50 grams of colour to 50 grams of developer, giving 100 grams of mixture.
Four Combinations and What They Need
The table below is what the page returns for four common scenarios. The most useful thing to notice is how coarse the bands are: the developer changes at specific lift values and then stays the same across a range.
- Level 4 to level 8 is a lift of four. Because anything beyond three levels falls into the strongest band, the page returns 40 volume at 12 percent with a processing window of 30 to 45 minutes and a caution note.
- Level 7 to level 9 is a lift of two, which sits in the middle band and returns 20 volume at 6 percent, again 30 to 45 minutes. This is the ordinary two-level blonde lift and needs nothing stronger.
- Level 5 to level 5 is no lift at all. The page returns 10 volume at 3 percent with a processing window of 15 to 25 minutes and describes it as deposit only or toning, which is correct — you are adding colour without removing any.
- Level 1 to level 6 is a lift of five, and the page returns 40 volume, the same as the four-level case. There is no stronger developer to escalate to, which is the honest answer: a five-level lift from black usually needs more than one process, and often bleach.
What Each Developer Volume Is For
| Alternative | Notes |
|---|
| 10 volume, 3 percent | Deposits colour and tones without meaningful lift. Used for going darker, refreshing faded ends and toning after lightening. The gentlest option and the only one safe for processing on the scalp repeatedly. |
| 20 volume, 6 percent | One to two levels of lift. The workhorse strength, and what most permanent colour in the shops is designed around. Also used for covering grey, where deposit matters more than lift. |
| 30 volume, 9 percent | Two to three levels. Enough to move a medium brown to a medium blonde in one application. More unforgiving of overlapping onto already-lightened hair. |
| 40 volume, 12 percent | Three to four levels, and the ceiling. The page flags it with a caution, correctly. It should not be applied to the scalp at all in most professional guidance, and it cannot be safely left on longer to achieve more — time is not a substitute for a second process. |
What the Calculation Cannot Account For
The level numbers are a simplified model. Real hair resists lifting in ways the difference between two digits cannot express.
- Previously coloured hair behaves differently from natural hair. Colour that has been deposited will not lift cleanly with the same developer, and artificial pigment often lifts through unwanted warm tones. The calculation assumes natural hair.
- Hair that has been box-dyed dark, or coloured with henna, can react unpredictably and in some cases cannot be lightened at all. This is the single most common reason a lift fails.
- Resistance varies along the length. Roots near the scalp process faster because of body heat, which is why professionals apply colour to the mid-lengths first.
- The arithmetic is deliberately conservative in one direction: because the page applies 40 volume to anything above three levels, it understates a five-level lift rather than overstating it. It never suggests a developer stronger than exists, and it never claims a single process will achieve what usually needs two.
Developer Questions
Why do zero lift and one level of lift both use 10 volume?
Because depositing and lifting by one level are handled by the same peroxide strength, and the difference between them shows up in the processing time instead — 15 to 25 minutes for a pure deposit against 20 to 30 for a one-level lift. The page keeps the two as separate entries so that timing difference is visible rather than hidden.
Does the mixing ratio change with the developer strength?
Not in the quantities the page reports, which use 50 grams of colour to 50 grams of developer for every combination — a 1:1 ratio. In practice a 1:2 ratio is sometimes used with high-lift colours and with some bleach products, and the page notes this. If the instructions that came with your product say 1:2, follow those, because the ratio affects how much the mixture lifts as well as how easily it spreads.
How much mixture do I need for my hair length?
100 grams covers a full-head application on hair to about shoulder length. Longer or thicker hair needs proportionally more, and it is better to mix a second batch of the same formula than to stretch one batch thin — an under-saturated application lifts unevenly, and the patchy result is much harder to correct than the extra product would have cost.
Should I do a patch test?
Yes, and a strand test as well, and these are two different checks. A patch test looks for an allergic reaction and is recommended for every new product. A strand test on a hidden section shows how your actual hair responds to that developer and that timing — which is the only way to learn whether the calculation's 30 to 45 minutes is right for your hair or needs shortening.
Last verified: October 3, 2026
Launch Hair Color Developer Calculator
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Maintained by Huang Bin · Last updated October 3, 2026