The cost of hair colour per service: how to work it out
The product cost of a colour service is the grams of each product × its price per gram, added up. Price per gram = pack price ÷ amount of product in the pack. A 60 g tube of colour for £10.00 costs £0.167 per gram, so 46 g of colour costs £7.67.
Step 1. Price per gram
price per gram = pack price ÷ amount of product in the pack (g)
- colour, 60 g for £10.00: £10.00 ÷ 60 = £0.167 per gram
- developer, 1000 g for £9.00: £9.00 ÷ 1000 = £0.009 per gram
Tubes and bottles often show volume in millilitres rather than weight. To work in grams precisely, weigh one full and one empty pack once. The difference is the amount of product.
Step 2. Grams from the scale
Weigh every product that goes into the bowl. If a visit has several mixes, say root colour and a toner for the lengths, count them all.
Step 3. Add it up: one visit as an example
| Product | Pack | Price | Per gram | Used | Cost |
|---|---|---|---|---|---|
| Colour 6.0 | 60 g | £10.00 | £0.167 | 31.8 g | £5.30 |
| Colour 7.1 | 60 g | £10.00 | £0.167 | 14.2 g | £2.37 |
| Developer 6% | 1000 g | £9.00 | £0.009 | 69.0 g | £0.62 |
| Total | 115.0 g | £8.29 |
There's one and a half times as much developer as colour in the bowl (a 1:1.5 ratio), yet colour accounts for over 90% of the cost of this mix.
Product cost calculator
What the colour left in the bowl costs
Leftover colour is product the salon has already paid for. Work out its cost from the average price per gram of the mix:
average price per gram = mix cost ÷ mix weight
leftover cost = leftover (g) × average price per gram
In the example above that's £8.29 ÷ 115.0 g = £0.072 per gram. If 6.4 g is left in the bowl, you throw away 6.4 × £0.072 = £0.46. At 200 colour services a month with the same amount left over, that's about £92 a month.
To know how much is left, you have to weigh it: the bowl with the leftover colour minus the empty bowl. It's easiest when every bowl has a number and its weight is saved once.
What else goes into the cost of a service
This formula covers product. The full cost of a service also includes extras such as a repair treatment, plus time, utilities and rent. Salons usually build those into the price list rather than counting them at the bowl.
Some salons charge clients for product by the gram. In that case, use the price per gram you charge instead of what you paid.
How Colour Lab does it
In Colour Lab you set the price per gram once for each product group, such as “Majirel colours” or “Developers”. It can be what you paid or what you charge clients. The app multiplies it by the grams from the scale, adds any extras and shows the total before you finish the service.
The app weighs leftover colour in numbered bowls with a barcode sticker and, at the next visit, scales the formula down to what the client used. More: leftover colour in Colour Lab.
Questions
How do I work out the price per gram of hair colour?
Divide the pack price by the amount of product in the pack, in grams. A 60 g tube for £10.00 costs £0.167 per gram.
Should developer count towards the cost of a colour service?
Yes. Developer is cheaper per gram, but there's usually more of it in the bowl than colour. At 1:1.5 there's one and a half times as much developer as colour.
How do I work out the cost of colour left in the bowl?
Weigh the bowl with the leftover colour, subtract the empty bowl, and multiply the result by the average price per gram of the mix: the mix cost divided by its weight.