Convert mm to Points and Inches to Points (PDF Units Cheat Sheet)
Developers, designers and print teams constantly switch between millimetres, inches and PDF points. This cheat sheet gives you the formulas and worked examples.
The only constants you need
- 1 inch = 72 points
- 1 inch = 25.4 millimetres
- 1 inch = 2.54 centimetres
Millimetres to points
pt = mm x 72 ÷ 25.4 (about mm x 2.8346)
Example: 210 mm x 2.8346 = 595.28 pt, the width of A4.
Inches to points
pt = inches x 72
Example: 8.5 in x 72 = 612 pt, the width of US Letter.
Centimetres to points
pt = cm x 72 ÷ 2.54 (about cm x 28.346)
Points back to mm and inches
mm = pt x 25.4 ÷ 72 and inches = pt ÷ 72.
In code
const MM_PER_INCH = 25.4
const PT_PER_INCH = 72
const mmToPt = (mm: number) => (mm * PT_PER_INCH) / MM_PER_INCH
const ptToMm = (pt: number) => (pt * MM_PER_INCH) / PT_PER_INCHSkip the math
If you only need to read a size, open the PDF in PdfRuler and pick the unit you want. It converts for you and keeps every measurement based on the PDF's own points. Learn more in what is a PDF point.
Frequently asked questions
How do I convert mm to PDF points?
Multiply millimetres by 72 and divide by 25.4 (about mm x 2.8346).
How do I convert inches to PDF points?
Multiply inches by 72.
