Which press-on size do I pick? How to measure your nails at home

A press-on set is ten nails, one per finger, in a single size — XS, S, M or L. Size is not about length (that gets filed) but about width: how wide each nail is, in millimetres. Measuring takes a minute per hand and is done once; after the first order you know your size.

How to measure

1. Take a ruler marked in millimetres, or a strip of paper and a pen.
2. Lay the ruler across the nail at its widest point — usually just below the middle, towards the cuticle. Read the width in millimetres from one side of the nail to the other, where nail meets skin.
3. If you are using paper: lay it across the nail, mark both edges with the pen, then hold the paper against the ruler.
4. Write it down for each finger: thumb, index, middle, ring, little. Five numbers per hand.
5. Measure both hands. They often differ by a millimetre.

How to read the table

In the size guide, each row is a size and each column a finger, with the width in millimetres. Put your five numbers next to each row and pick the row that matches most of them. All five do not have to match exactly — a 1 mm difference on one finger is within the normal margin.

• XS: thumb 14 mm, index 10, middle 11, ring 10, little 8.
• S: 15 / 11 / 12 / 11 / 9.
• M: 16 / 12 / 13 / 12 / 10.
• L: 17 / 13 / 14 / 13 / 11.

If you are between two sizes

Take the larger one. The sides of a press-on can be filed a little for an exact fit; a nail that is too small cannot be stretched, and the strip of natural nail left uncovered shows and catches. A millimetre too much is fixed with ten seconds of filing; a millimetre too little is not fixed.

If your fingers do not all match the same row

That is normal. Almost nobody has exactly the proportions in the table — an M thumb with an S little finger is ordinary. The rule: pick the size by the three middle fingers (index, middle, ring), because they are the ones seen most and the hardest to adjust. The thumb and little finger get their sides filed if needed.

Why it matters

• A nail too wide touches the skin at the sides, lifts from there and comes off on day one.
• A nail too narrow leaves a strip of natural nail at the edge, and it shows that it is a press-on.
• One that fits sits bonded across its whole surface and looks like yours, only longer.

How to file the sides

With the press-on still off, held between your fingers, file the side in short strokes in one direction, checking often against the finger. File a little at a time: a millimetre in total means half a millimetre on each side. Adjust the shape of the tip now too, before it goes on — far easier than afterwards.

What if I got the size wrong

If it is one size too big, file the sides — solved. If it is one size too small, it cannot be corrected; before ordering again, re-measure the three middle fingers, this time at the widest point rather than near the tip. The most common measuring error is reading the width towards the tip, where the nail is narrower.

Once it fits, a set is worn several times if you take it off carefully — the method is here. And the designs are on the press-on shelf.