A size 3 in one nail set is not guaranteed to match a size 3 in another. Numeric tip codes identify pieces within a product’s own sizing system; they are not universal measurements.
Keep your measurements and your successful product-specific sizes as separate records.
What a number can mean
A number on the underside helps sort tips in that range. It may correspond to a width in the manufacturer’s chart, but the number itself is not a millimeter value.
Before reordering, confirm whether the style uses the same tip system. A new shape, length, or product line may use a different chart even under the same brand.
Letter sizes bundle several fingers
XS, S, M, and L may describe a bundle of ten sizes. A bundle that suits most fingers can still miss one thumb or little finger.
Read the individual measurements or codes included in the bundle. Ask whether mixed sizes, single replacements, or a sample kit are available.
Shape changes the fitting experience
Width is only one dimension. Crosswise curve, lengthwise arch, cuticle outline, and side taper also matter.
Even two charts listing the same width can use different measuring methods. Check whether the numbers describe the inner surface, outer surface, or a straight span.
Build a useful size record
- Save the exact product line, shape, and length.
- Record all ten codes in left- and right-hand order.
- Keep the chart or screenshot used for the order.
- Note any permitted filing and the result.
- Add a photo of the comfortable dry fit.
Label an unsuccessful fit too. “Thumb too curved” is a more useful note than simply writing “size too small.”
When changing ranges
Start with the new chart and compare its method to your measurements. Use the old code as a reference only, not a direct conversion.
If the information remains unclear, ask the seller before buying. A sizing kit can be worthwhile when a full decorated set is expensive or replacements are limited.