Hair Developer Volume Calculator (10, 20, 30, 40)
Not sure whether to reach for 20 or 30 volume? Pick what you want to do and get the right developer strength, the percentage equivalent and the expected lift.
Good to know: Standard choice for 100% white coverage with permanent color at the natural level.
20 vs 30 volume
20 vol (6%) lifts 1–2 levels and is gentler, so it is your go-to for gray coverage. 30 vol (9%) lifts 2–3 levels with more processing — reach for it when you need extra lift.
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Developer volume and percentage chart
10 vol = 3%: deposits only, refreshes or slightly darkens with no lift.
20 vol = 6%: covers gray and lifts 1–2 levels — the everyday standard.
30 vol = 9%: lifts 2–3 levels for stronger lightening.
40 vol = 12%: only for products and techniques that explicitly permit it; never on the scalp.
20 vs 30 volume developer explained
20 vol (6%) lifts 1–2 levels gently and is commonly used for gray coverage and tone-on-tone work. 30 vol (9%) lifts 2–3 levels with more cuticle swelling and processing. Follow the product instructions and choose the lowest volume that reaches your target level.
Frequently asked questions
Which developer volume should I use?
10 vol (3%) deposits only, 20 vol (6%) covers gray and lifts 1–2 levels, and 30 vol (9%) lifts 2–3 levels. Use 40 vol (12%) only when the product and technique explicitly permit it, and never on the scalp.
What's the difference between 20 and 30 volume?
20 vol (6%) lifts 1–2 levels and is gentler; 30 vol (9%) lifts 2–3 levels with more processing. Use 20 vol for gray coverage and 30 vol when you need extra lift.
What developer for toner or bleach?
Use 10–20 vol for toner or gloss. For on-scalp bleach, 20 vol is commonly used; off the scalp, use 30 vol only when the product instructions allow it. Never exceed the product maximum.