About GreyCover

Covering or working with grey hair usually comes with a handful of questions that a bottle of box color doesn’t answer on its own. Is 20% grey light enough for a demi-permanent gloss, or does it need a full permanent tint? What developer volume actually matches the job — depositing tone, covering grey, or lifting a few levels? How much color and developer should actually go in the bowl for a head of medium-length hair? How many months until color grows all the way out to natural grey? How often do roots really need touching up before they show? And once silver strands start looking brassy or yellow, how much toner and developer, and for how long? None of these are hard questions individually, but working them out by hand, every time, is where a simple color job turns into guesswork.

GreyCover exists to take that guesswork off your plate. Instead of long articles you have to read end to end, the site is built around a set of small, single-purpose calculators, each aimed at one part of the process. The Gray Coverage Calculator takes your grey percentage, hair length, and texture and recommends a color type, developer volume, and mix strength. The Developer Volume Calculator matches the standard 10/20/30/40-volume convention to what you’re actually trying to do — deposit, cover grey, or lift a set number of levels. The Color Mix Ratio Calculator works out exact color and developer amounts in grams for a standard 1:1 or high-lift 1:2 mix, scaled to hair length. The Going Gray Timeline estimates how many months it takes to grow out colored hair to natural grey, with 25/50/75/100% milestones along the way. The Root Touch-Up Scheduler turns a growth rate and a visible-root threshold into a practical number of weeks between appointments. And the Toner Mix Calculator gives exact toner and developer amounts, plus a process-time guide, for neutralizing brassiness and yellow tones on grey or silver hair.

Beyond the calculators, the blog and learn section cover grey coverage, color formulation, and the reasoning behind the numbers the tools produce, and the Hair Museumis a browsable collection of the anatomy, biology, and chemistry behind hair itself — from the follicle and its pigments to the science of going grey and the chemistry of hair dye — with every entry, image, and fact drawn from Wikipedia and Wikimedia Commons.

A few things worth stating plainly. GreyCover is an independent site, not affiliated with any hair-color brand, salon chain, or cosmetology board. It is supported by advertising, which is how the tools stay free with no account required. Every result the tools produce — a color type, a developer volume, a mix amount, a grow-out timeline, a touch-up interval, a toner mix — is a general estimate built on the numbers you enter and on common hair-color conventions, not a professional cosmetology or medical determination, and GreyCover is not a salon. Always patch-test a new product first and follow that product’s own instructions, which take priority over any general estimate here; for hair with a complex chemical history, a scalp condition, or an allergic reaction to a previous color, check with a licensed colorist or a doctor before proceeding. If something looks off in a tool or an article, or you think a calculator is missing that would help, the contact page is the place to say so.