How to use the typography converter
- Type the size in Value.
- Choose its unit in From and the unit you want in To: pixels, points, picas, inches, millimetres, centimetres, Q, em, rem or % of font size.
- Leave Resolution at 96 px per inch for web work, or set your print or image resolution, such as 300.
- Set Base font size in px if your root size is not 16. It is used for em, rem and %.
- Read the result and the table. The swap button reverses From and To.
What it does and when to use it
Designers move between print units (points, picas, millimetres) and screen units (pixels, em, rem) all the time. A brand guide may say 10 pt body text and 18 mm margins, while the CSS needs px or rem. A print designer may need to know how many pixels a 24 pt headline covers in a 300 ppi image. This tool does those conversions with one set of settings that you can see and change.
For a quick list of rem values across a whole scale, the px to rem converter and the CSS type scale generator work well together. For page sizes in points and pixels, use the paper size converter. To find a screen’s real pixel density, use the PPI calculator.
How it works
Every value is turned into inches and then into the target unit. The fixed relationships come from the CSS absolute-length definitions, which match modern DTP software:
| Unit | Inches |
|---|---|
| point (pt) | 1/72 |
| pica (pc) | 1/6 (12 pt) |
| millimetre | 1/25.4 |
| centimetre | 1/2.54 |
| Q | 1/101.6 (0.25 mm) |
| pixel | 1 ÷ Resolution |
| em, rem | Base font size ÷ 96 |
| % | (value ÷ 100) × Base font size ÷ 96 |
At the default 96 px per inch this gives the familiar web values: 1 pt = 1.333 px, 1 in = 96 px, 1 mm ≈ 3.7795 px.
Worked examples
Body text for the web. 12 pt = 16 pixels (px) at 96 px per inch. The table also shows 1 em, 100 % and 4.23333333333 mm.
A rem heading. 1.5 rem = 24 pixels (px) with the default 16 px root, which is 18 pt.
Print resolution. At a Resolution of 300, 24 px is only 5.76 points (pt, 1/72 in), because each pixel is now 1/300 inch.
Limits and tips
- Base font size is in CSS pixels (1/96 in) whatever the resolution, so a 16 px base is always 12 pt; 1 em at 300 px per inch is 50 device pixels.
- Nested em values are not tracked; enter the parent’s font size as the base.
- Point systems older than DTP (Didot, the American point of 0.3514 mm) are not included.
Frequently asked questions
How many pixels is 12 pt?
What is the difference between em and rem?
What is a pica?
What is the Q unit?
Does a 16 px font look the same size on every screen?
Sources
- CSS Values and Units Module Level 3, section 6.2 Absolute lengths — W3C, accessed 2026-10-08
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