Formula
px = mm × 96 ÷ 25.4
20mm = 75.5906px. CSS defines this ratio as fixed.
Millimetres to CSS pixels at the spec-defined 96 DPI.
Converter
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mm to px conversion table
| mm | px | Rounded |
|---|---|---|
| 1mm | 3.77953px | 3.78px |
| 2mm | 7.55906px | 7.56px |
| 3mm | 11.33858px | 11.34px |
| 4mm | 15.11811px | 15.12px |
| 5mm | 18.89764px | 18.9px |
| 6mm | 22.67717px | 22.68px |
| 8mm | 30.23622px | 30.24px |
| 10mm | 37.79528px | 37.8px |
| 12mm | 45.35433px | 45.35px |
| 15mm | 56.69291px | 56.69px |
| 20mm | 75.59055px | 75.59px |
| 25mm | 94.48819px | 94.49px |
| 30mm | 113.38583px | 113.39px |
| 40mm | 151.1811px | 151.18px |
| 50mm | 188.97638px | 188.98px |
| 60mm | 226.77165px | 226.77px |
| 80mm | 302.3622px | 302.36px |
| 100mm | 377.95276px | 377.95px |
| 148mm | 559.37008px | 559.37px |
| 210mm | 793.70079px | 793.7px |
| 297mm | 1122.51969px | 1122.52px |
Questions
How do I convert mm to px?
px = mm × 96 ÷ 25.4. So 20mm = 75.5906px.
Is the mm to px conversion exact?
Yes, for CSS. The specification fixes 1in = 96px, which pins every absolute unit to a fixed ratio regardless of the physical display. It is not a physical measurement — a CSS inch on a phone is not an inch of glass. For real-world output size use the DPI calculator instead.
How do I convert px back to mm?
Invert the formula, or use the px to mm converter.
Other conversions
Conversions follow the CSS Values and Units specification, in which 1in is defined as exactly 96px. Values are computed, not tabulated by hand.