Typography converter

The PostScript point — exactly 1/72 of an inch — is the reference unit here, and most other entries are simple multiples of it: a pica is 12 points, an inch is 72 points, and a pixel at the standard 96-dots-per-inch screen density is 0.75 points, which is why 12-point text so often renders as 16 pixels on the web.

Metric sizes convert through the inch definition, so a millimeter comes out to roughly 2.8346 points and a centimeter to 28.3465 points. The Didot point and its cicero (12 Didot points, mirroring how a pica is 12 points) are the parallel system long used in French and other European typesetting, sized slightly larger than the PostScript point. The twip — literally "twentieth of a point" — is 0.05 points and turns up mostly inside word-processor and rich-text file formats, while the agate, at 5.5 points, is a traditional unit newspapers use to price classified and column advertising, and the em here is pinned to a 16-pixel base font, making it equal to 12 points. Knowing that an em at that assumed base equals 12 points is particularly useful when translating a CSS stylesheet's relative sizing into the fixed point sizes a print layout tool expects.

The point-to-pixel rule is px = pt × 1.333333333, and the reverse direction multiplies by 0.75.

Body text set at 12 pt converts to 16 px on a 96-dpi screen. A single pica converts to about 4.2333 millimeters — the same figure you'd get from dividing an inch into six parts and converting that to metric directly. Reversing the examples, 4.2333 millimeters converts back to almost exactly 1 pica, and 16 px converts back to exactly 12 pt, confirming both directions of the formula line up.

Print designers working in page-layout software think in points and picas because those units map directly onto press measurements, web and UI designers work in pixels or em because that's what browsers render, and anyone handling older European print files or legacy word-processor documents will run into Didot-system or twip-based measurements that need translating before they make sense in a modern layout tool.

A pixel has no fixed physical size on its own — the 0.75-point-per-pixel relationship here assumes a 96-dpi reference, and a genuinely different pixel density (a 300-dpi print proof, a high-density phone screen) would need a different factor entirely, so pixel-to-point conversions are only as accurate as the DPI assumption behind them. It's also worth remembering that em is a relative unit tied to whatever font size is active, so the 12-point figure used for em here only holds at the 16-pixel base size this table assumes.

It's worth knowing that the PostScript point used throughout this table (exactly 1/72 inch) is a slightly different, cleaner definition than the traditional pre-digital printer's point used in older hot-metal typesetting, which was close to but not identical to 1/72 inch. Modern design and publishing software has standardized on the PostScript definition, so contemporary point-based conversions like the ones here stay consistent regardless of which application produced the original file. It also helps to remember that the agate and twip exist for narrow, specific purposes — classified-ad pricing and word-processor internals, respectively — so encountering either one outside those contexts is a strong hint that a file-format conversion, not a genuine measurement choice, is behind the number.