What Developer Do You Use for a Root Touch-Up?
The short answer
Use 10 volume when the root only needs to deposit, 20 volume when you need up to two levels of lift on natural regrowth, and 30 volume only on resistant grey that will not take at 20. Never use 40 volume on the scalp, and never treat previously lightened regrowth as natural hair.
Updated
Choosing the developer
- 1Match the target level to the natural level. Deposit only means 10 volume.
- 2Up to two levels of lift means 20 volume at the manufacturer ratio.
- 3Resistant grey that reads warm or misses at 20 volume means 30 volume, with a strand check first.
- 4If the regrowth has any previous lightener in it, drop one volume step and watch the development instead of trusting the timer.
Grey coverage specifics
Grey is more resistant than pigmented hair, which is why the same root formula that lifts beautifully on pigmented regrowth can sit flat and warm on grey.
The fix is usually the formula rather than the developer: add a natural or base series at roughly half the mix, and choose a target level one lighter than the client wants so the result lands where they expect.
Use the tool
What Developer Ratio Do I Need? Colour Mix Calculator
Enter colour weight and ratio, get the developer weight in grams — no login, no signup.
Open the calculator →Frequently asked
Can I use 20 volume on the scalp for grey coverage?
Yes, 20 volume on the scalp is standard for grey coverage. Use a natural series at about half the mix so the grey reads covered rather than transparent.
What if the root lift goes too warm?
That is the exposed undertone, not the developer. Tone it at the bowl with the complementary tone rather than re-developing with a stronger formula.
Keep reading
- What Formula Covers Resistant Grey?Permanent, one level lighter than target, 20 volume, natural series at half — and why grey goes hot.
- Which Developer Volume Lifts How Many Levels?What each volume can and cannot do, and why the standard rule breaks on resistant grey and lightened hair.
- What Developer Ratio Do I Need? Colour Mix CalculatorEnter colour weight and ratio, get the developer weight in grams — no login, no signup.
- What Formula Takes Dark Hair to Blonde Safely?Two sessions, not one: staged lift with lightener, then toning to the target shade.
Part of Formulas in the S2 Academy.