Points to Inches Converter
| Points | Inches | mm | The size in life |
|---|---|---|---|
| 7 | 0.0972 | 2.47 | newspaper agate |
| 9 | 0.125 | 3.18 | compact print body |
| 12 | 0.1667 | 4.23 | one pica, the document default |
| 18 | 0.25 | 6.35 | quarter-inch display |
| 36 | 0.5 | 12.7 | half-inch headline |
| 72 | 1 | 35.28 | the full-inch letter |
A type point is one seventy-second of an inch - 0.3528 millimeters, exact by modern definition - and every font size you have ever set is a count of them: 12-point text stands on a twelfth of an inch, 72 points makes one full inch of type. Type either number and the converter lands the other.
The ladder above the point is the pica: twelve points to a pica, six picas to the inch, and layout programs still measure line lengths in picas the way printers did. The FAQs cover the two questions that always follow - why old TeX documents use 72.27 points to the inch, and why a 12-point letter is nowhere near a twelfth of an inch tall.
How to use
- Type the point size from a style guide or word processor - inches and the millimeter equivalent land instantly, or run the reverse.
- Read the table for the working sizes: 12 points is one pica, 18 a quarter inch of type, 72 the full inch.
- Line lengths in layout programs are set in picas and points together (22p6 means twenty-two picas six points) - convert picas by multiplying by twelve first.
Frequently asked questions
Is a point always exactly 1/72 inch?
The modern desktop point is - PostScript fixed it at exactly 1/72 inch in the 1980s, and screens and printers have followed since. But typesetting history carries two older values: the 19th-century American printer's point was 0.0138372 inches, which is why TeX still divides the inch into 72.27 points, and continental Europe's Didot point sits at about 0.376 millimeters. When a document's numbers look subtly off, check which century's point it is using.
Why is 12-point text not 12/72 of an inch tall?
Because the point measures the em - the type designer's nominal body size - not any actual letter. A capital letter usually tops out around 70 percent of the em, lowercase x-height nearer half, and the rest is internal leading and descender room. Two fonts at the same 12 points can visibly differ in size for exactly this reason: the em box is the same, the letters inside it are not.
What is a pica and who still uses it?
Twelve points - a sixth of an inch. Printers set type with pica rulers, and InDesign and its cousins still default to picas for line lengths and margins because the arithmetic stays in whole numbers: a 40-pica column is 480 points, six and two-thirds inches. The abbreviation mixes units freely - 22p6 means twenty-two picas and six points.
How big is normal body text in millimeters?
Books and reports sit at 9 to 12 points, which is 3.2 to 4.2 millimeters of em - roughly a third of what people guess when asked to size type by eye. Newspaper agate runs 7 points at the small end, large-print editions start near 16. The table converts the sizes a style guide actually names.
Didot, American, PostScript - does the difference matter?
Only at the edges. Within one document the three systems differ by under two percent - a 12-point Didot em is 4.51 millimeters against the PostScript 4.23 - but a book measured in one system and printed in another accumulates the drift line by line. Modern font files bury the question by declaring their own units-per-em, which is why the 1/72 point won: it is the one every screen speaks.