NaillyGrowing out a bad set, bitten nails, or damage from a bad removal always takes longer than people expect. Here's the actual math, so you can set a timeline that matches reality instead of guessing.
The base rate
Fingernails grow about a tenth of a millimeter per day — roughly 3mm, or about a tenth of an inch, per month. At that rate, a full fingernail growing out from the cuticle to where it's long enough to file at the tip takes somewhere between four and six months. Toenails grow much slower, closer to a year to a year and a half for a full cycle, which is part of why toenail damage takes so long to visibly resolve.
What speeds growth up (and what doesn't)
A handful of factors genuinely move the rate: your dominant hand's nails grow slightly faster than your non-dominant hand's, longer fingers grow faster than shorter ones, and pregnancy measurably speeds up nail growth through hormonal and circulation changes. Age works the other direction — nail growth is fastest in childhood, drops by about half after puberty, and slows gradually from there, losing roughly half a percent of speed per year starting around 25.
What doesn't meaningfully move the rate: biotin supplements beyond a normal baseline, cuticle oil, or any topical product. These support the quality of what grows in — fewer peels, less brittleness — but they don't speed up the underlying rate the nail matrix is producing new keratin.
Growing out damage specifically
If the goal is growing out a damaged section — from over-filing, a peeled-off gel set, or nail biting — the honest timeline is: you'll see meaningful new, healthy growth at the base within 3–4 weeks, but the damaged section itself won't be filed off until it's grown far enough past the cuticle to trim, which is the same four-to-six-month window as full regrowth. There's no way to accelerate past that; the nail matrix produces new nail at a fixed rate regardless of how badly the visible nail is damaged.
This is exactly the situation BIAB and other builder gel overlays are built for — not speeding up growth, but protecting the nail while it does the growing, so a bad snag at week two doesn't reset the whole timeline.
Setting a realistic expectation
If someone tells you a product will "grow your nails faster," that's not how nail biology works — there's no topical or oral intervention proven to increase the underlying growth rate beyond correcting an actual nutritional deficiency. What genuinely changes the outcome is protecting what's already growing: gentle removal, consistent refills instead of letting product grow out and lift, and cuticle hydration. Four to six months is the real number for a full natural-nail cycle — plan around that, not around a faster promise.