When ordering buttons, you will often see sizes like 16L, 18L, 24L or "24 lignes". This refers to the international unit of measurement, the "ligne" (L), used in the garment industry. Here is how to interpret it.
What is a ligne (L)
One ligne is approximately 0.635 mm (1/40th of an inch). Therefore, 40 lignes are about 25 mm. The formula is simple: diameter in mm = lignes × 0.635. In Bulgaria, the designation "pp" is also often used – it is the same as L.
Size chart
| Lignes (L / pp) | Millimeters | Typical use |
|---|---|---|
| 14L | 9 mm | shirt collar, children's clothing |
| 16L | 10 mm | shirts, blouses, cuffs |
| 18L | 11.5 mm | shirt front |
| 20L | 12.5 mm | thicker shirts, blouses |
| 24L | 15 mm | cardigans, dresses, light jackets |
| 28L | 18 mm | jackets, cardigans |
| 32L | 20 mm | jackets, coats |
| 36L | 22 mm | jackets, coats |
| 40L | 25 mm | coats |
| 44L | 28 mm | coats, trench coats |
| 54L | 34 mm | large coats and decoration |
How to measure a button
- Place the button on a ruler or caliper.
- Measure the widest diameter – from edge to edge, excluding the shank.
- Round to the nearest standard size from the table.
If you are replacing a button, measure the buttonhole as well – the button should be 2–3 mm smaller than the length of the buttonhole.
Frequently asked questions
What size button is for a shirt?
Most commonly 16L (10 mm) for the collar and cuffs, and 18L (11.5 mm) for the front. See our shirt buttons.
Are L and pp the same?
Yes, it is the same unit of measurement with a different designation.
