How much developer to add to hair colour? Ratios in grams from 1:1 to 1:5
A 1:X ratio means X grams of developer for every gram of colour. Developer = grams of colour × X. For 40 g of colour at 1:1.5, that's 40 × 1.5 = 60 g of developer, and the whole mix weighs 100 g.
Developer calculator
Chart: grams of developer for a given amount of colour
| Colour | 1:1 | 1:1.5 | 1:2 | 1:3 | 1:5 |
|---|---|---|---|---|---|
| 10 g | 10 g | 15 g | 20 g | 30 g | 50 g |
| 20 g | 20 g | 30 g | 40 g | 60 g | 100 g |
| 30 g | 30 g | 45 g | 60 g | 90 g | 150 g |
| 40 g | 40 g | 60 g | 80 g | 120 g | 200 g |
| 50 g | 50 g | 75 g | 100 g | 150 g | 250 g |
| 60 g | 60 g | 90 g | 120 g | 180 g | 300 g |
| 70 g | 70 g | 105 g | 140 g | 210 g | 350 g |
| 80 g | 80 g | 120 g | 160 g | 240 g | 400 g |
| 90 g | 90 g | 135 g | 180 g | 270 g | 450 g |
| 100 g | 100 g | 150 g | 200 g | 300 g | 500 g |
| 120 g | 120 g | 180 g | 240 g | 360 g | 600 g |
| 150 g | 150 g | 225 g | 300 g | 450 g | 750 g |
What 1:1.5 or 1+1.5 means
Both mean the same: the first number is the colour, the second the developer. “1+2” on the box means 1:2, twice as much developer as colour.
The ratio tells you nothing about the developer strength (3%, 6%, 9% or 12%, also sold as 10, 20, 30 or 40 volume). You choose the strength separately, based on the colour's technical sheet and the result you're after.
A mix of several shades
Work out the developer from the total of all the colours in the bowl, not shade by shade.
30 g of 7.1 + 15 g of 8.0 = 45 g of colour
45 g × 1.5 = 67.5 g of developer
whole mix: 45 g + 67.5 g = 112.5 g
If the bowl also has additives, such as pigments or boosters, check with the manufacturer whether they count as colour for the ratio.
Poured too much developer? How to fix the ratio
Work out how much colour the developer already in the bowl calls for, and add the difference.
colour needed = developer in the bowl ÷ X
to add = colour needed − colour in the bowl
Example: the bowl has 45 g of colour, the ratio is 1:1.5, and 75 g of developer went in instead of 67.5 g. 75 ÷ 1.5 = 50 g, so you're 5 g of colour short.
With several shades, add the missing colour in the same proportions as the bowl. For 30 g of 7.1 and 15 g of 8.0 (2:1), that's about 3.3 g of 7.1 and 1.7 g of 8.0.
Grams or millilitres?
This chart assumes you weigh. Some manufacturers give ratios in millilitres, and colour and developer have different densities, so 60 ml doesn't always weigh 60 g. If the technical sheet gives millilitres and you work with a scale, ask the manufacturer or your supplier how to convert.
How Colour Lab does it
With Colour Lab there's nothing to work out by hand. Scan the developer, choose the ratio, and the app tells you how many grams to add to the colour already weighed in the bowl.
Colour in the bowl: 45.0 g
- 1:1
- 45.0
- 1:1.5
- 67.5
- 1:2
- 90.0
- 1:3
- 135.0
- 1:5
- 225.0
More about what the app records for every mix: the developer panel and formulas in Colour Lab.
Always follow the colour manufacturer's instructions for developer ratio and strength. This page shows how to work out the grams, not which ratio to use.
Questions
How much developer for 60 g of colour?
At 1:1, 60 g; at 1:1.5, 90 g; at 1:2, 120 g; at 1:3, 180 g; and at 1:5, 300 g of developer.
What does a 1:2 ratio mean?
2 g of developer for every 1 g of colour. 30 g of colour needs 60 g of developer, and the whole mix weighs 90 g.
Is developer worked out from the whole mix?
No, from the colour only: the total of all shades in the bowl. The whole mix is colour plus developer.
How do I know which ratio to use?
Check the box or the colour's technical sheet. The same brand can use different ratios for different lines, for example permanent colour and a high-lift range.