How often you need a root touch-up comes down to how fast your hair grows and how visible your grays are against your color. For most people that's every 3-6 weeks; gray coverage usually lands at the tighter end.
The 4-week rule for grays
Hair grows about half an inch every four weeks, so by week four you typically have a visible line of regrowth at the part and hairline. That's why gray coverage is commonly a 4-week cadence, about 13 touch-ups a year, while people with subtler regrowth can stretch to six weeks.
What changes your cadence
Faster-growing hair, a stark contrast between your grays and your dyed color, and a part or hairline that shows roots first all push you toward more frequent touch-ups. Cooler, closer shades and a bit of strategic styling can buy you extra time.
How cadence turns into touch-ups per year
The gap between touch-ups is the single biggest lever on your annual cost. Same coverage, very different counts:
- Every 3 weeks: about 17 touch-ups a year, the fast-growth, high-contrast end.
- Every 4 weeks: about 13 a year, the typical gray-coverage cadence.
- Every 5 weeks: about 10 a year.
- Every 6 weeks: about 9 a year, realistic only for subtler regrowth.
Cutting the count without showing roots
A temporary root concealer covers regrowth until your next wash, letting you push a touch-up out by a week or two. Fewer touch-ups means lower annual cost: run your own cadence through the root touch-up calculator to see how a week here or there changes your yearly total, and our guide to stretching salon visits has more ways to lengthen the gap.