The one rule behind every mixing ratio
Most of the mixes I have watched go wrong went wrong in the bowl, before the brush touched the hair. Runny cream sliding off the section, or bleach that had set into a paste. Nine times out of ten the product was fine and somebody, sometimes me, had the ratio off.
Ratio is written color first, developer second, and it is by weight. 1:1 means equal grams of each. 1:1.5 means one and a half times as much developer as color. 1:2 means twice as much developer. The calculator above does the multiplication and turns it into tubes and ounces.
Everything else on this page is that rule applied to one product or another.
Which ratio for which product
The brand decides. It is on the tube and on the technical sheet, and usually on the developer bottle too (nobody reads the developer bottle, which is a pity, since the ratio is often printed larger there). The presets cover the ratios you will meet most often, as a default to check against the tube.
| Product | Typical ratio | Why |
|---|---|---|
| Permanent cream (most US professional lines) | 1:1 | Thick cream, needs an equal weight of developer to become workable and fully develop. |
| Permanent cream (many European lines) | 1:1.5 | More concentrated pigment, formulated for a looser mix that spreads on long hair. |
| High-lift blonde series | 1:2 | The extra peroxide is what gives the extra lift. Cutting the developer share cuts the lift and does nothing for the color. |
| Demi-permanent, liquid or gel toner | 1:2 | Deposit only. The higher developer share keeps the result sheer and even on porous, lightened hair. |
| Bleach powder | 1:1.5 to 1:2 | Thicker for on-scalp control, thinner for foils and balayage where you need it to spread and stay moist. |
Where the calculator stops helping is the range. Bleach is listed at 1:1.5 to 1:2 and the tool gives you either end to the gram, but stiff for a scalp or loose enough to stay wet in a foil is a call about the technique and the room, and there I go by how it falls off the brush.
Why grams, not milliliters
Developer is mostly water, so 1 ml is about 1 g and a measuring cup works for it. Cream color is denser and it traps air when you squeeze it, and then a third of what you did measure stays smeared inside the cup. Two colorists measuring "60 ml" of cream can end up with 50 g and 68 g in the bowl, and on a scale both of them get 60 g.
A digital kitchen scale that reads to 1 g costs less than one tube of color. Bowl on the scale, zero it, squeeze color to the target, zero it again, pour developer to the second target. I zero twice every time, even for a 10 g dab, because subtracting from a running total in your head is the sort of arithmetic that goes wrong at four in the afternoon with a client watching in the mirror. I have never liked the plastic cups that come in the kits; in my chair they go straight in the drawer, and some colorists would argue with that.
The scale converted me. For years I squeezed half tubes by eye, the way everyone I trained under did, and I was confident about it, the way you get confident about anything you have never checked. Then one slow afternoon I squeezed what I knew was half a 60 g tube into a bowl sitting on the new scale. 22 g. I had already poured 30 g of developer for it, so that mix was thinner than the tube intended, and I thought back over the gray coverage complaints I had put down to the client's hair or the water. Some of those were probably me. One of them I redid two weeks later on my own time, another tube of color and most of a morning. I still squeeze by eye when I am in a hurry. But the bowl is on the scale while I do it and I stop when the number says stop.
Starting from the total instead
Sometimes you know how much you need in the bowl (a full head of long hair wants 120 to 150 g of mixture) and want to know how to split it. Switch the calculator to "Total in the bowl". For a 1:1.5 mix at 150 g total, that is 60 g of color and 90 g of developer, because 150 divided by 2.5 parts is 60 per part. The dye amount calculator estimates the total from the hair itself if you are not sure where to start.
Ratio versus volume: two different dials
People mix these up because both are numbers on the bottle. Volume is peroxide strength: 10, 20, 30, 40. It decides how much lift you get and how gently or aggressively the cuticle opens. Ratio is quantity, how much of that developer goes in relative to color. Volume changes the chemistry, ratio only changes how concentrated and how thick the mix is, so you choose them separately: the brand fixes the ratio for the line, you pick the volume for the level change, and the level chart covers how much each volume can lift.
Mistakes that look like product problems
- Eyeballing half a tube. A 60 g tube squeezed "to the middle" is rarely 30 g, and the tube gives no feedback either way.
- Adding developer to fix thickness. A 1:1 mix is supposed to feel stiff. Loosening it dilutes the pigment and weakens gray coverage.
- Reusing a ratio across lines. Switching from a 1:1 brand to a 1:1.5 brand and mixing 1:1 gives a thick, over-pigmented mix that processes unevenly.
- Mixing bleach by volume. Powder settles in the tub, so a scoop from a fresh tub and one from a half-empty tub weigh differently even when they look the same.
- Forgetting additives. Bond builders and mixing oils add weight and liquid. Follow the additive's own dosing and count it as part of the developer share if the brand says so.
Small batches and touch-ups
The ratio does not care how small the batch is. A 10 g dab for a hairline is 10 g of color and 15 g of developer at 1:1.5, and the scale reads it fine. What changes is waste. Small mixes dry out fast, so use it straight away and do not save the leftovers, because mixed color with developer keeps working for about 30 to 45 minutes and then loses its strength.