How to convert CSS pixels to CSS millimetres
mm = px × 0.264583333333333
Multiply the px reading by 0.264583333333333.
Worked examples
16 px ≈ 4.233333333 mm
16 × 0.264583333333333 ≈ 4.233333333
Font basis for this example: element 16 px; root 16 px.
24 px ≈ 6.35 mm
24 × 0.264583333333333 ≈ 6.35
Font basis for this example: element 16 px; root 16 px.
Frequently asked questions
Which font or display assumption applies?
em and rem depend on the specified font context. CSS absolute units have fixed relationships to reference pixels, which do not necessarily equal physical display pixels.