What Volume Developer Should I Use For Bleach?

October 27, 2026

FarmaVita Life Cream Developer 1000ml bottles in 10, 20, 30 and 40 vol beside the question What volume developer for bleach?

Picking the developer is one of the first decisions you make at the mixing bowl, and it shapes the whole lightening service. The right strength depends on two things: the lightener you're using, and whether the mix will touch the scalp.

Here's the short answer. Use 20 vol (6%) for anything on the scalp. Only go up to 30 or 40 vol for work off the scalp, such as highlights, and only when your lightener's instructions list it.

For professional use. Always follow the manufacturer's instructions for your lightener and developer.

To find out more about using a low-volume mix to lighten softly, read How to bleach bath hair.

What do 10, 20, 30 and 40 vol developer mean?

The volume tells you how strong the developer is. Each step up adds about 3% hydrogen peroxide:

10 vol: about 3%
20 vol: 6%
30 vol: 9%
40 vol: 12%

It's worth checking the % on the bottle as well as the vol, as it's the clearer of the two. In the UK, 12% (40 vol) is the most a hair product can contain once it's mixed.

What volume developer for bleach on the scalp and roots?

For roots and anything else on the scalp, 20 vol is the one to reach for. It's the usual maximum for lightener on the scalp.

If your lightener lists stronger developers but doesn't give an on-scalp limit, check the leaflet before you start on the roots.

When can you use 30 or 40 vol developer?

Stronger developers are for work off the scalp, such as highlights and freehand techniques, and only when your lightener lists them. Some lighteners allow 30 vol for highlights, and clay lighteners made for freehand work can take up to 40 vol.

Brands don't all describe off-scalp work in the same way, so check your own lightener's wording before you go above 20 vol.

Working on a dark base? It's tempting to reach for a stronger bottle, but let a strand test show you what your chosen strength will do first. The scalp limit still applies, however dark the hair.

Does a higher volume developer lighten more?

Yes. In the same lightener, a stronger developer gives more lift. Check your lightener's chart for the lift and the time at each strength.

Every lightener is different, though, and your client's hair plays a part too. That's why the strand test always has the final say.

How do you mix and use developer with bleach?

Whichever strength you choose, the service follows the same order.

Skin test before the appointment. Follow your lightener's pack for how and when. If your client has reacted to a hair product before, ask them to speak to a pharmacist or GP before you go ahead.
Put on gloves. Wear them for every mix, including the strand test, and to apply and rinse.
Do a strand test with a small separate mix. Mix a little lightener and developer at the pack's ratio and check the strand as the pack directs.
Prepare the hair as the pack says. Some lighteners go on dry hair, so check before you start.
Mix the main bowl fresh. Mix it just before you apply it and use it straight away.
Develop within the pack's limits. Never go past the maximum time, and don't add heat or a cap unless the pack allows it.

Pro Tip: The bowl is weaker than the bottle. Mix 1 part powder to 2 parts 20 vol and you're starting at roughly 4% peroxide, so the mixing ratio matters as much as the volume.

Keep an eye on the bowl as you work. If the mix foams, steams or gets hot, stop, rinse and seek medical advice. And wear gloves every time: the persulphates in bleach powder are a common cause of allergy among hairdressers, whatever developer you use.

If lightener gets in the eyes or irritates the skin, rinse with cool running water straight away and get medical advice.

Quick answers on developer and bleach

What developer do you use with bleach powder?
The one your lightener is made to work with, usually a cream developer. Many brands make a developer to pair with their own lightener, so check the pack.

What bleach can you use with 20 volume developer?
20 vol works with most professional lighteners. Just use the mixing ratio on the pack.

10 vol or 20 vol developer for bleach?
20 vol is the usual choice. 10 vol is the gentlest strength, but many professional lighteners start at 20 vol, so only use 10 vol if your lightener lists it.