NaillyPress-on nails have earned their renaissance — modern sets are gel-quality, reusable, and a fraction of salon cost. But every press-on disappointment traces back to the same root: sizing. A press-on that is even half a millimetre too wide lifts at the edges, pops off in a pocket, and convinces people the whole category is flimsy. It is not; it is mis-sized. Here is how to measure properly, what the numbers mean, and the tricks that make a set fit like it was sculpted on.
Why sizing is the whole game
A press-on stays on through surface contact: adhesive needs the entire underside of the tip touching nail. Too wide and the edges bridge over your nail's curve, leaving air channels that water finds within a day. Too narrow and a strip of your nail sits exposed at each side, catching and peeling. The correct size matches your nail's width at its widest point — the line just below where nail meets skin at the sides — within about a quarter millimetre.
How to measure your nails
You need: a flexible measuring tape (or a strip of paper and a ruler) and five minutes.
1. Measure straight across each nail at its widest point, in millimetres. Do not follow the curve — measure the straight-line width as a bird sees it.
2. Write all ten down. Your two hands are not identical — nobody's are — so measure both rather than doubling one.
3. Compare against the brand's size chart, not a generic one. A “size 4” has no universal meaning; each brand's millimetre mapping differs.
4. When you fall between sizes, go smaller for wear (edges sealed beats edges bridged) and larger only if you plan to file the sides down — which good sets tolerate well.
Fit tricks the frequent flyers use
Dry-fit the whole set first. Number the tips with a marker on the underside before any adhesive appears.
File to your sidewalls. A tip that is right at the base but a touch wide at the free edge can be side-filed after application — that is finishing, not failure.
Match the curve, not just the width. If your nails are notably flat or notably arched, look for brands that state their C-curve; a mismatch there shows up as pressure at the centre or gaps at the edges.
Prep like a tech. Push cuticles back, buff the shine off, wipe with alcohol. Adhesive bonds to nail, not to oil.
Glue or tabs?
Glue wears one to two weeks and treats the set as semi-permanent; adhesive tabs wear a day or three and preserve both your nail surface and the tips for reuse. The honest answer for most people: tabs for occasions, glue for vacations, and a proper gel set for everything longer.
Size once, use it forever
The tedious part — measuring — only has to happen once if the numbers live somewhere useful. Nailly's design studio lets you design a set to your own shape and length before you buy or book anything, and when you send a design to an artist through the city board, your sizing details ride along with the request — so whether the set ends up as press-ons, Gel-X or a salon sculpt, it is built for your actual hands, not the average ones.