Typography Unit Converter
Inputs
| Points | 12 |
|---|---|
| Resolution | 96 |
Typography Unit Converter
Convert between typographic units — points, picas, millimetres, inches, and pixels — with adjustable screen resolution.
Typography Units
Pixel
Typography Units
Typography uses its own measurement vocabulary — points, picas, millimetres, and pixels — each suited to a different part of the design workflow. This converter handles all four, plus the screen-dependent pixel conversion that requires knowing the display resolution.
Point: the base unit of typography
The PostScript point (abbreviated pt) is defined as exactly 1/72 of an inch, or approximately 0.3528 mm. Introduced by Adobe in the 1980s and adopted by CSS, PDF, macOS, and iOS, it is now the universal standard in digital typography and desktop publishing.
The older Didot point used in French and European print tradition is larger (approximately 0.376 mm, or 1/72.27 of an inch), and the pre-digital American printer's point is approximately 0.351 mm. Neither is used in contemporary software.
Pica
A pica equals 12 points, or 1/6 of an inch (approximately 4.233 mm). Picas are convenient for specifying column widths and margins in print layout: a standard US letter page (8.5 in) is 51 picas wide, and a two-column layout at a quarter-inch gutter is easily specified in whole picas.
The CSS abbreviation is pc (font-size: 1pc equals 12pt).
Millimetres and inches
Converting between points and metric or imperial lengths is straightforward because the PostScript point is anchored to the inch:
Common reference values: 10 pt = 3.528 mm; 12 pt = 4.233 mm (one pica); 72 pt = 1 inch. These conversions are resolution-independent — they depend only on the fixed definition of the point, not on the display device.
Millimetre values are most useful when preparing print-ready artwork or specifying type sizes to a print bureau. Inch values align with North American page dimensions (US letter, US legal) where column widths are often expressed in fractions of an inch.
Points to pixels: resolution matters
Converting points to pixels requires knowing the screen resolution:
The CSS reference density is 96 DPI, where 1 inch = 96 px. At this density, 12 pt equals px, and 1 pt equals px.
At 72 DPI — once the standard Mac screen density — 1 pt maps exactly to 1 px.
Modern high-DPI screens (such as 326 DPI Retina displays) apply a device pixel ratio so that the software pixel behaves as if the screen were at a lower reference density. A CSS pixel on a Retina display at 326 DPI with a 2× device pixel ratio corresponds to roughly 163 logical DPI; enter 163 when calculating native app layout at the logical pixel layer (for web CSS, the browser handles DPR automatically and 96 DPI remains the correct input).
Worked example
A type specimen uses 10.5 pt body text. To verify this fits a 60 mm column at standard web resolution:
mm=10.5×7225.4≈3.704 mm per line px=10.5×7296=14 pxA 10.5 pt type size is 14 px in a browser, and the type body is approximately 3.7 mm tall on paper.
Frequently Asked Questions (FAQ)
What is a typographic point?
A typographic point is the smallest unit of measurement in traditional and digital typography. The modern standard is the PostScript (DTP) point, defined as exactly 1/72 of an inch (approximately 0.3528 mm). This definition is used by CSS, PDF, macOS, iOS, and virtually all contemporary design software, including Adobe Illustrator and InDesign.
What is the difference between a point and a pixel?
A point (pt) is a fixed physical unit: 1/72 of an inch, regardless of screen resolution. A pixel (px) is a device-relative unit whose physical size depends on the display resolution.
On a 96 DPI display (the CSS reference density), 1 pt equals 4/3 px (≈ 1.333 px). On a 72 DPI display, 1 pt equals exactly 1 px. On a high-DPI display such as a 326 DPI Retina screen, 1 CSS px covers multiple physical device pixels through device pixel ratio scaling.
What is the difference between a PostScript point and a traditional point?
The PostScript (DTP) point is defined as exactly 1/72 of an inch (0.352 778 mm). The older French typographic point (Didot point) is larger at approximately 0.376 mm, and the British/American printer's point is approximately 0.351 mm. The PostScript point has been the universal standard in digital typography since Adobe introduced it in the 1980s, and is the definition used by this converter.
What DPI should I use for web or CSS conversions?
For web and CSS work, use 96 DPI. The CSS specification defines 1 inch as exactly 96 CSS pixels, making 1 point (1/72 inch) equal to 96/72 ≈ 1.333 CSS pixels. This is the reference density regardless of the physical screen resolution — high-DPI screens handle the scaling internally via device pixel ratio. Use 72 DPI only for legacy macOS or print contexts where 1 pt = 1 screen pixel was assumed.
What is a pica in typography?
A pica is a typographic unit equal to 12 points, or 1/6 of an inch (approximately 4.233 mm). Picas are widely used to specify column widths, margins, and leading in print layout and desktop publishing. The abbreviation is "pc" in CSS and "P" or "p" in traditional typesetting notation. Six picas make one inch; 72 points and 6 picas are therefore equivalent.
Disclaimer
This converter uses the PostScript (DTP) point definition: 1 pt = 1/72 inch. Pixel values are CSS reference pixels computed at the resolution entered in the DPI field. Results may differ from print-specific or legacy platform contexts that use a different point definition.
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