Use this conversion to compare CSS length values under an explicitly chosen pixel basis, such as a root font size, element font size, viewport dimension, or physical-unit convention.

CSS length

Required string input.

Root font size (px)

Required number input.

Element font size (px)

Required number input.

Viewport width (px)

Required number input.

Viewport height (px)

Required number input.

Convert px, rem, em, vw, and vh CSS lengths to pixels using explicit root, element, and viewport dimensions; unsupported units are rejected. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Computed length (px)

The resulting computed length returned as a number.

• Many CSS units are contextual rather than absolute. rem, em, percentages, viewport units, container units, zoom, device pixel ratio, and font metrics can produce different used values across elements and rendering environments.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Verify the computed style in the target browser and layout context. Prefer responsive CSS relationships over pre-converting every value when the design is meant to adapt.

• Pixels To Rem 16base

  CSS rem units from CSS pixels using a 16-pixel root font size.

• Rem To Pixels 16base

  CSS pixels from rem units using a 16-pixel root font size.

• Ems to Pixels Converter

  Convert a length in ems to pixels for a root font size.