Convert

Millimetre to CSS pixel

Exact answer: 1 mm = 3.779527559055 px (exact defined factor)

Millimetre and CSS pixel 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 mm

Result3.779528 px

Factor1 mm = 3.779527559055 px

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

Examples

011 mm = 3.779528 px

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 mm = 2.83464566929 pt. Then the value is converted through the base unit pt into CSS pixel.

Table

Millimetre to CSS pixel
Millimetre	CSS pixel
1	3.779528
2	7.559055
5	18.897638
10	37.795276
25	94.488189
100	377.952756

Formula

1 mm = 2.83464566929 pt. Then the value is converted through the base unit pt into CSS pixel.

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

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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 Millimetre to CSS pixel?

1 mm = 3.779527559055 px

Which formula does Millimetre to CSS pixel use?

1 mm = 2.834645669291 pt. Then the value is converted through the base unit pt into CSS pixel.

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.