Tools
Typography calculator
Typography unit calculator
Convert between points, picas, ciceros, agates, inches and millimetres.
Used for em and rem calculations
About this tool
The typography calculator converts one measurement into ten units at once: pixels, points, picas, agates, ciceros, inches, millimetres, centimetres, em and rem. It is useful when you move a print layout to the web or the other way round, when a printer quotes measurements in picas or ciceros, or when you need to know how many millimetres a 10-point type size is.
Type the value into “Convert from” and choose its unit from the drop-down. “Converted values” shows the same measurement in every unit. Click any row to make it the source unit and carry on from there. For em and rem, set the “Base font size” first; it defaults to 16 px. Underneath there is a quick reference with the most common equivalences.
Everything is calculated in your browser and no data is sent anywhere. The tool uses the CSS convention of 96 pixels per inch and the PostScript point of 1/72 inch, so pixels here are not the physical pixels of your screen. The cicero is taken as 4.512 mm (12 Didot points). It does not work out line heights or paper sizes; there are separate tools for those on this site.
How do I use the typography calculator?
- Type the value you have in “Convert from” and choose its unit in the drop-down (for example, 10 and “points”).
- Read the same measurement in pixels, points, picas, agates, ciceros, inches, millimetres, centimetres, em and rem under “Converted values”.
- If you are working with em or rem, set the “Base font size” first (16 px by default in browsers).
- Click any result row to use it as the new source unit and carry on converting from there.
Typographic equivalents worth knowing
They all derive from the inch, which is exactly 25.4 mm. The digital typographic point (PostScript point) is 1/72 of an inch, about 0.3528 mm, which is why 72 points make an inch. A pica is 12 points, that is 1/6 of an inch or about 4.233 mm.
On the web, CSS sets 96 pixels per inch, so 1 point equals 1.333 px and 12 pt is 16 px, the default browser font size. Rem uses that root font size as its reference: with a 16 px base, 1 rem is 16 px; em uses the font size of the parent element.
The cicero comes from the European Didot system: 12 Didot points, about 4.512 mm, slightly larger than a pica. The agate, once used in newspapers to measure columns and ads, is 1/14 of an inch, about 1.814 mm.
From print to screen: which unit to use when
For print and documents (InDesign, Word, PDF), the usual practice is to work in points for type size and leading, and in millimetres for margins and page formats. Body text in print usually sits between 9 and 12 points depending on the typeface and medium.
For the web, it is best to set type in rem: it respects the size each person has chosen in their browser and scales everything in proportion if they enlarge it. Pixels are still useful for borders and fine details.
When you move a print design to the web, the “physical size” is not preserved: a screen is viewed at a different distance and density. Use the conversion as a starting point and always check the result on a phone and a computer.
Frequently asked questions
How many millimetres is a typographic point?
A PostScript point is 1/72 of an inch, or roughly 0.3528 mm. A 12 pt type size is therefore about 4.23 mm.
What is a pica?
A pica is 12 points, or 1/6 of an inch (about 4.23 mm). Layout designers often use it to measure column widths.
How does a cicero differ from a pica?
The cicero is the traditional European unit: 12 Didot points, about 4.512 mm. It is slightly larger than the Anglo-American pica, which is about 4.233 mm.
How many pixels is 12 points?
In CSS, 12 pt is 16 px, because there are 96 px and 72 pt to the inch. The actual physical size on screen can vary with the device's pixel density.