What goes down the sink
A half-inch root touch-up on an average head takes about 30 g of color. A standard tube holds 60 g. Mix the whole tube at 1:1 and there is 120 g in the bowl, 60 g goes on the head, and 60 g gets rinsed away: 30 g of color and 30 g of developer.
Touch-ups come round every five or six weeks, so call it ten a year. That is 300 g of color per client in the drain, five whole tubes, plus the same weight of developer. I started counting after a Saturday when the color bar bin held four bowls with mix still in them, all touch-ups from the whole tube. Call it 30 g of color in each: two tubes, paid for and scraped into the bin. Not a fortune on the day. But the bin gets emptied every day, and nothing about that Saturday was unusual except that I looked, and I have weighed ever since.
Root touch-ups
Regrowth sets the amount; the band is the same size at chin or waist, so the calculator ignores length for a touch-up. Half an inch on medium-density hair is 30 g of color, a quarter inch 20 g, an inch 40 g, past an inch and a half 50 g.
Thirty grams is half a tube. Squeeze onto a zeroed scale until it reads 30 and cap the rest, which keeps for weeks with the cap on tight. I lost half a tube of a level 6 neutral last winter to a cap left loose on a dirty thread, top inch set hard, the rest gone dark, so now the date and grams left go on masking tape. Stubborn gray at the hairline is the usual reason for extra; when more product does not fix it, try the gray coverage calculator.
Full heads
On uncolored hair the color has to coat every strand, so length takes over. Chin length is 40 g of color, shoulder 60 g, mid-back 90 g and waist 120 g, all at medium density. Developer goes on top at the tube's ratio (nobody reads the tube): shoulder length at 1:1.5 is 60 g of color and 90 g of developer, 150 g in the bowl.
Roots plus a refresh uses the full root amount for the regrowth and half the full-head amount for the lengths, since previously colored ends only need a sheer pass.
Long hair
Past the shoulders, people under-mix far more than they over-mix. Mid-back needs 90 g of color and waist length 120 g, two full tubes before a drop of developer.
Density hides on long hair.
One waist-length client got 90 g for roots and refresh for two years, and every visit I was scraping the bowl at the nape. She looked medium. Fine, flat at the crown. The ponytail measured a touch over 4 in, thick in the calculator, so her number is 115 g and I had been 25 g short every visit.
Once the total passes 200 g, split it and mix the second half fresh when you get to it; color and developer start reacting the moment they meet, and a bowl that sits twenty minutes has lost strength before the last section. The processing time calculator covers the clock from there.
Toners and glosses
Toner is thinner than permanent cream and usually mixed 1:2, so it travels further per gram. A whole-head gloss needs about 60 percent of the full-head amount: 35 g at shoulder length where a full head is 60 g.
Toners and demi-permanents go on 10 volume developer, deposit only, usually on damp, towel-dried hair, which helps the product move; a 35 g toner at 1:2 is 105 g in the bowl.
What pushes the number up
- Density. More hairs per square inch, more surface to coat. Thick hair takes about 30 percent more; fine hair 20 percent less.
- Porosity. Porous, previously lightened ends drink product; budget an extra 10 percent.
- Curl. Curly and coily hair carries more length than it shows and product has to be worked in, so it uses more.
- Length. It compounds with the rest: thick, curly, waist-length hair tops every table on this page.
The calculator cannot see how the hair takes product; two clients with the same ponytail measurement can be 10 or 20 g apart, so after the first visit I go by feel and write the number on the card.
The 10 percent rule
Whatever the calculator says, mix about 10 percent more. Running out with two sections left is worse than 5 g of waste: a second batch mixed in a hurry is never identical, and the hair that gets it late processes differently.
The exception is toner, where over-mixing is cheap and under-mixing shows as patchy warmth, so round up. And strand test anything new, whatever the amount.
Grams by service and length
Color only, at medium density. Fine hair times 0.8, thick hair times 1.3. Developer on top by ratio.
| Service | Chin | Shoulder | Mid-back | Waist |
|---|---|---|---|---|
| Root touch-up, 1/2 in regrowth | 30 g | 30 g | 30 g | 30 g |
| Full head, uncolored hair | 40 g | 60 g | 90 g | 120 g |
| Roots (1/2 in) plus refresh | 50 g | 60 g | 75 g | 90 g |
| Gloss or toner, whole head | 25 g | 35 g | 55 g | 70 g |
Touch-ups by regrowth: 1/4 in 20 g, 1/2 in 30 g, 1 in 40 g, 1.5 in and over 50 g.
- Half-inch roots: 30 g of color. Half a tube, not a whole one.
- Shoulder-length full head: 60 g of color. One tube.
- Thick hair times 1.3, fine hair times 0.8.
- Developer on top by the tube's ratio; weigh it, do not pour it.
- Mix 10 percent extra. Over 200 g total, split into two bowls.
What it saves
Take a chair doing 20 color services a week. If each one is mixed from a whole tube when it needed half, that is 30 g of color and its developer thrown away twenty times: 600 g a week, ten tubes, around 40 tubes a month. At $10 a tube it is $400 a month before developer, from one chair, for the price of a scale and thirty seconds of weighing.
I have never liked the argument that product is cheap next to chair time; in my chair it comes out of my margin. Weigh the color, add developer with the mix calculator at the manufacturer's ratio, and put the half tube back with the tape on.