Convert

CSS pixel to Millimetre

Exact answer: 1 px = 0.264583333333 mm (exact defined factor)

CSS pixel and Millimetre describe the same quantity from the Typography family but come from different systems of units. The factor is defined exactly. Typography links point, pixel and millimetre across print, web and layout.

Unit console

Convert units with formula, context and precision

UnitCloud is a local measurement lab for everyday work, engineering, IT, energy, mobility and design. Every conversion shows result, formula, base unit, rounding and the common mistake.

What do you want to convert?

From1 px

Result0.264583 mm

Factor1 px = 0.264583333333 mm

Source basisNIST Guide to SI Appendix B · W3C CSS Values and Units

Examples

011 px = 0.264583 mm

Example value from the reference table. Internal calculation uses stored factors; display output is rounded.

02Common mistake

px depends on output context. UnitCloud uses the CSS reference of 96 px per inch.

03Base unit: pt

1 px = 0.75 pt. Then the value is converted through the base unit pt into Millimetre.

Table

CSS pixel to Millimetre
CSS pixel	Millimetre
1	0.264583
8	2.116667
16	4.233333
32	8.466667
96	25.4
300	79.375

Formula

1 px = 0.75 pt. Then the value is converted through the base unit pt into Millimetre.

Sources

NIST Guide to SI Appendix BNIST conversion-factor method and non-SI factors.W3C CSS Values and UnitsCSS reference units for px, pt and in contexts.

Related conversions

Point to CSS pixelpt → pxTypography CSS pixel to Pointpx → ptTypography Millimetre to Pointmm → ptTypography Point to Millimetrept → mmTypography

Search and practice paths

FormulaTableExamplesCommon mistakeEveryday/engineeringExcel/CSVBatch converterPrint view

Data rateReading internet speed correctly

Factor origin

Factors come from the stored source family and are not derived from rounded display values.

Rounding rule

UnitCloud keeps calculating with stored factors and rounds only the displayed output by selected precision.

When not to use

Do not use as the sole basis for official, medical, safety-critical or contractual decisions.

Citation

Citation note: UnitCloud, conversion with formula, sources reviewed: September 2026. Typography. Source basis: NIST Guide to SI Appendix B · W3C CSS Values and Units.

Common questions

What is the factor for CSS pixel to Millimetre?

1 px = 0.264583333333 mm

Which formula does CSS pixel to Millimetre use?

1 px = 0.75 pt. Then the value is converted through the base unit pt into Millimetre.

What is the most common mistake?

px depends on output context. UnitCloud uses the CSS reference of 96 px per inch.

When should I verify the result?

Do not use as the sole basis for official, medical, safety-critical or contractual decisions.