Pt to mm converter

Converting pt to mm is simple: one point is 1/72 inch, so 25.4 ÷ 72 = 0.3528 mm. A 12 pt font therefore has a body (em square) 4.23 mm high.

Example: Value 12 · Unit: Point (pt, DTP) · Resolution for pixels 96 dpi → Result: 12 pt = 4.233 mm. Source: NIST SP 811, Appendix B.8: inch = 2.54 E−02 m, point (computer) (1/72 in) = 3.527 778 E−01 mm, pica (computer) (1/6 in), point (printer’s) = 3.514 598 E−01 mm (read 10.10.2026). Updated: 10 October 2026.

Value

Unit

Resolution for pixels

dpi

The OpenType specification: a VGA display under Windows is treated as a 96-dpi device; most laser printers have 300 dpi or more.

My ToolboxYour inputs are saved in this browser only.

Result

Result: 12 pt = 4.233 mm
In all units: Unit Value
Millimeters 4.233 mm
Centimeters 0.423 cm
Inches 0.1667 in
Picas (12 pt) 1 pica
Pixels at the chosen resolution 16 px
Printer’s point (NIST) 12.045 printer’s pt; At 12 pt the em square is 4.23 mm high, which is 16 px at 96 dpi. The letters themselves are usually smaller: according to the OpenType specification the em square typically covers the full body height of the font plus some extra spacing. DTP point = exactly 1/72 inch (calculated from 1 inch = 25.4 mm); the older printer’s point is slightly smaller at 0.3514598 mm.

Unit	Value
Millimeters	4.233 mm
Centimeters	0.423 cm
Inches	0.1667 in
Picas (12 pt)	1 pica
Pixels at the chosen resolution	16 px
Printer’s point (NIST)	12.045 printer’s pt

How it is calculated

1 pt = 1/72 inch = 0.3528 mm, and 1 mm = 2.835 pt. So 12 pt type measures 4.23 mm – that is the height of the em square, not of a single letter. This is the DTP or computer point; NIST lists it as “point (computer) (1/72 in)” with 0.3527778 mm.

Font sizes: pt to mm and pixels

pt	mm	px at 96 dpi
6	2.12	8
8	2.82	10.7
10	3.53	13.3
11	3.88	14.7
12	4.23	16
14	4.94	18.7
16	5.64	21.3
18	6.35	24
24	8.47	32
36	12.7	48
72	25.4	96

The pixel column follows the formula in the OpenType specification: pixels per em = point size × resolution ÷ 72. At 96 dpi – how Windows treats a VGA display according to the specification – 12 pt is 16 px; at 300 dpi it is 50 px.

Why are letters smaller than the point size?

The point size describes the em square: according to the specification it is exactly 9 points high at 9 pt (3.175 mm) and typically covers the full body height of the font plus some extra spacing so that lines do not collide. A capital letter is therefore usually well below 4.23 mm at 12 pt – how much depends on the typeface. If you need a specific letter height in millimeters, measure a test print.

Printer’s point and picas

Besides the DTP point, NIST lists the older printer’s point at 0.3514598 mm; 12 of them are 4.218 mm instead of 4.233 mm. A pica is 12 points = 1/6 inch = 4.233 mm. How large an image prints from its pixel size is worked out by the print size calculator; for web pages in rem and em there is the px to rem converter, and A4, Letter and other sheet sizes are listed under paper sizes.

Frequently asked questions

How many mm is 12 pt?

4.23 mm (12 × 25.4 ÷ 72). That is the height of the em square, not of a letter.

How do I convert pt to mm?

pt × 0.3528 – exactly pt × 25.4 ÷ 72. The other way: mm × 2.835 = pt.

How many points are 1 mm?

2.835 pt (72 ÷ 25.4).

How many pixels is 12 pt?

16 px at 96 dpi, 12 px at 72 dpi and 50 px at 300 dpi (point size × dpi ÷ 72).

What is a pica?

12 points = 1/6 inch = 4.233 mm (NIST: “pica (computer) (1/6 in)”).

What is the difference from the printer’s point?

NIST gives the older printer’s point as 0.3514598 mm and the DTP point as 0.3527778 mm – about 0.4 % larger.

Sources and legal basis

As of: 10 October 2026 · Editorial policy