Unit & Measurement Tables
Typography Size Conversion Table
Type sizes are the last corner of design still measured in a pre-metric unit. A point is 1/72 of an inch, a definition inherited from metal type, and a pica is twelve of them. Print designers have used these numbers for four centuries, and print software still reports page sizes in points even when the country has been metric for generations.
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The web added a second layer. CSS defines the reference pixel as exactly 1/96 of an inch, so a CSS pixel is not a physical pixel on most screens — it is a logical unit that browsers scale. Because both the inch and the point are anchored to that same inch, the conversion between them is exact: 1 pt = 4/3 px and 1 px = 0.75 pt. There is no rounding anywhere in the relationship.
That exactness is worth knowing because it explains a coincidence people notice but rarely understand: 12 pt equals 16 px, which is why 16 px became the default body size in browsers and why print specs of 10 to 11 pt map to web sizes of 13 to 15 px. The two systems are not roughly compatible, they are the same system with different units.
What does not convert is em and rem. Those are relative units — em is the current font size, rem is the root font size — so a value in em has no fixed pixel equivalent until you know what it is relative to. Any table claiming a fixed em-to-px ratio is assuming a 16 px root, which is a default rather than a rule.
Points to pixels, picas and millimetres
| Points | Pixels (CSS) | Picas | Millimetres |
|---|---|---|---|
| 6 | 8.00 | 0.5000 | 2.117 |
| 7 | 9.33 | 0.5833 | 2.469 |
| 8 | 10.67 | 0.6667 | 2.822 |
| 9 | 12.00 | 0.7500 | 3.175 |
| 10 | 13.33 | 0.8333 | 3.528 |
| 11 | 14.67 | 0.9167 | 3.881 |
| 12 | 16.00 | 1.0000 | 4.233 |
| 14 | 18.67 | 1.1667 | 4.939 |
| 16 | 21.33 | 1.3333 | 5.644 |
| 18 | 24.00 | 1.5000 | 6.350 |
| 20 | 26.67 | 1.6667 | 7.056 |
| 24 | 32.00 | 2.0000 | 8.467 |
| 28 | 37.33 | 2.3333 | 9.878 |
| 32 | 42.67 | 2.6667 | 11.289 |
| 36 | 48.00 | 3.0000 | 12.700 |
| 48 | 64.00 | 4.0000 | 16.933 |
| 60 | 80.00 | 5.0000 | 21.167 |
| 72 | 96.00 | 6.0000 | 25.400 |
12 pt is 16 px exactly — the default body size in every browser. A pica is 12 points, so the picas column is just points divided by 12.
Pixels to points, picas and millimetres
| Pixels | Points | Picas | Millimetres |
|---|---|---|---|
| 10 | 7.50 | 0.6250 | 2.646 |
| 12 | 9.00 | 0.7500 | 3.175 |
| 14 | 10.50 | 0.8750 | 3.704 |
| 16 | 12.00 | 1.0000 | 4.233 |
| 18 | 13.50 | 1.1250 | 4.762 |
| 20 | 15.00 | 1.2500 | 5.292 |
| 24 | 18.00 | 1.5000 | 6.350 |
| 30 | 22.50 | 1.8750 | 7.938 |
| 32 | 24.00 | 2.0000 | 8.467 |
| 36 | 27.00 | 2.2500 | 9.525 |
| 40 | 30.00 | 2.5000 | 10.583 |
| 48 | 36.00 | 3.0000 | 12.700 |
| 56 | 42.00 | 3.5000 | 14.817 |
| 64 | 48.00 | 4.0000 | 16.933 |
| 72 | 54.00 | 4.5000 | 19.050 |
| 96 | 72.00 | 6.0000 | 25.400 |
A 16 px paragraph is 12 pt in print terms. When a print designer asks for 10 pt, the web equivalent is 13.33 px.
Named sizes as they appear in print and on screen
| Name | Points | Pixels (CSS) | Typical use |
|---|---|---|---|
| Pearl | 5 | 6.67 | Fine print |
| Nonpareil | 6 | 8.00 | Legal footnotes |
| Brevier | 8 | 10.67 | Captions |
| Bourgeois | 9 | 12.00 | Dense tables |
| Long primer | 10 | 13.33 | Trade paperback body |
| Small pica | 11 | 14.67 | Comfortable body text |
| Pica | 12 | 16.00 | Web default body |
| English | 14 | 18.67 | Subheadings |
| Great primer | 18 | 24.00 | Section headings |
| Double pica | 24 | 32.00 | Page titles |
The traditional names are still used in book design. The pixel column is computed at 96 px per inch, the CSS reference density, not at a physical screen's density.
Page dimensions in the three units that matter for print
| Format | Millimetres | Points | Pixels at 96 dpi |
|---|---|---|---|
| A4 | 210 × 297 | 595 × 842 | 794 × 1123 |
| A5 | 148 × 210 | 420 × 595 | 559 × 794 |
| US Letter | 216 × 279 | 612 × 792 | 816 × 1056 |
| US Legal | 216 × 356 | 612 × 1008 | 816 × 1344 |
| A3 | 297 × 420 | 842 × 1191 | 1123 × 1587 |
These are the numbers that appear when a PDF or a print dialog reports a page size. A4 in points is 595.28 × 841.89 before rounding.
How to Use These Tables
- Print to web: multiply points by 1.3333 to get CSS pixels. A 10 pt caption is 13.33 px, and a 12 pt body is 16 px.
- Web to print: multiply pixels by 0.75 to get points. A 24 px heading is 18 pt, which is what a print designer would call great primer.
- Page geometry: A4 in points is 595 × 842, which is the number PDF tools report. Multiply millimetres by 2.8346 to get points.
- Picas: divide points by 12. A 36 pt headline is 3 picas, and a 6 pica column is 72 pt wide.
- Screen density: a CSS pixel is 1/96 inch by definition, so a 96 dpi print of a web page matches the browser's layout at 100% zoom.
Common Questions
Is 12 pt the same as 16 px?
Yes, exactly. CSS defines 96 px per inch and 72 pt per inch, so 12 pt is 12 × 4/3 = 16 px. The two are not approximations of each other.
Why is a CSS pixel not a real pixel?
Because screens have different densities. CSS anchors one pixel to 1/96 inch and lets the browser scale, so on a high-density display one CSS pixel covers several physical pixels. The layout stays consistent while the rendering sharpens.
How many points is an inch?
72. That is the definition of the point, and everything else in typography follows from it: a pica is 12 pt, so there are 6 picas in an inch.
Can I convert em to pixels?
Only if you know the reference size. One em equals the current font size, so at a 16 px body, 1.5 em is 24 px. If the root changes, every em value changes with it.
What is A4 in points?
595 × 842 points, which is what a PDF reports. The exact figure is 595.28 × 841.89, because 210 mm is 595.2756 pt.
Why do print sizes use points instead of millimetres?
Because the point predates the metric system and print equipment was built around it. In countries that use ISO paper, the sheet is defined in millimetres but the type on it is still specified in points.
More Unit & Measurement Tables
Sources
- CSS Values and Units Module Level 4 — absolute length units — W3C
- ISO 216 — Writing paper and certain classes of printed matter — International Organization for Standardization
- NIST Handbook 44 — Appendix C, units of measurement — National Institute of Standards and Technology
Filed with Unit Conversion calculations.