Press-On Nail Size Calculator
Measure the width of each nail in millimetres and enter the five numbers. The calculator gives the press-on size number (0 to 9) for each finger and the closest ready-made set (XS, S, M or L).
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Measure
Enter the width of each nail in millimetres, measured across the widest part with a strip of tape laid flat on a ruler.
Enter the width of each nail in millimetres to see your press-on sizes.
How it works
Press-on nails are sized by width, measured in millimetres across the widest part of the nail. The sizes are numbered 0 to 9 and the numbers run backwards: size 0 is the widest nail and size 9 is the narrowest.
This calculator uses a simple and widely used chart, with 1 mm between sizes: 0 = 18 mm, 1 = 17 mm, 2 = 16 mm, 3 = 15 mm, 4 = 14 mm, 5 = 13 mm, 6 = 12 mm, 7 = 11 mm, 8 = 10 mm, 9 = 9 mm. As a formula, size = 18 minus your nail width in mm, with the width rounded up to the next whole millimetre first. So a nail that falls between two sizes gets the wider one, because a press-on that is slightly too wide can be filed narrower at the sides and one that is too narrow cannot be fixed.
Ready-made sets are usually sold as XS, S, M and L. The calculator compares your five widths (thumb, index, middle, ring, pinky) with a chart several makers publish: XS = 14, 10, 11, 10, 7 mm. S = 15, 11, 12, 11, 8 mm. M = 16, 12, 13, 12, 9 mm. L = 17, 13, 14, 13, 10 mm. It picks the set with the smallest total difference from your nails, and the larger set if two are equally close.
To measure, lay a strip of clear tape across the widest part of the nail, from one side wall to the other. Mark both edges of the nail on the tape with a pen, peel the tape off, stick it flat on a ruler or a sheet of paper and measure between the marks in millimetres. Measuring flat tape, not the curved nail from above, is what gives the right width.
What it cannot tell you
- There is no official standard for press-on sizes. Makers' charts agree closely at the wide end and can differ by 1 to 2 mm at the narrow end, so one brand's size 6 can be another brand's size 7. If the brand you are buying from publishes its own chart, use that chart and the millimetre widths shown here.
- Width is only part of the fit. A press-on also has a curve, and a very flat or very curved nail may need one size up or down. A sizing kit from the maker is the surest check before ordering a custom set.
- Your two hands often differ by a size on one or two fingers. Measure both hands if you are ordering a made-to-measure set.
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Common questions
To measure your nails for press-ons, put a strip of clear tape across the widest part of each nail and mark the two edges of the nail on the tape. Peel the tape off, lay it flat and measure between the marks in millimetres. Do this for all five nails on a hand, because each finger usually needs a different size.
Press-on nail sizes 0 to 9 are width codes, and a smaller number means a wider nail. On a widely used chart size 0 is about 18 mm wide and size 9 is about 9 mm wide, with about 1 mm between sizes. The numbers are not standardised, so the exact widths change from brand to brand.
If your nail is between two press-on sizes, choose the larger (wider) one. A press-on that is a little too wide can be filed down at the sides to fit. One that is too narrow leaves a gap and tends to lift, and it cannot be made wider.
A medium press-on set is usually about 16 mm for the thumb, 12 mm for the index finger, 13 mm for the middle finger, 12 mm for the ring finger and 9 mm for the pinky. Makers differ by a millimetre here and there, so check the widths in the brand's own chart instead of relying on the letter.
No, press-on nail sizes are not the same for every brand. Most brands number their nails 0 to 9 from widest to narrowest, but the width behind each number can differ by 1 to 2 mm. Always compare your measurements in millimetres with the chart of the brand you are buying.