How to use it
- Type the size and choose its unit.
- For em or rem, set the base font size in px (browsers default to 16 px).
- Read the same size in every unit below.
Definitions used
| Unit | Relation |
|---|---|
| 1 inch | 96 px = 72 pt = 6 pica = 25.4 mm |
| 1 point (pt) | 1/72 inch = 4/3 px |
| 1 pica (pc) | 12 pt = 16 px |
| 1 em / rem | the base font size in px |
| 1 cm | 10 mm = 1/2.54 inch |
Worked example
Body text of 11 pt is 11 × 96 ÷ 72 = 14.67 px, which is 0.9167 rem at a 16 px base and 3.88 mm tall. A 210 mm wide A4 sheet is 210 ÷ 25.4 × 96 = 793.7 px.
Tips
- These are CSS definitions; DTP software may use a different point (such as a traditional 0.3515 mm or 1/72.27 inch).
- Font size is not the visible height of letters: it is the em box, so capitals are smaller than the size in pt.