Use this typography calculation when the font metrics, writing system, layout direction, rendering environment, and measurement units are known.

Font Size Pixels (px)

Required number in px.

Tracking Em (em)

Required number in em.

The cited overview of Typography supplies background for the terminology and domain context used by this tool.^[1]

CSS letter spacing in pixels from font size and tracking expressed in em units. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Letter Spacing Pixels (px)

Returned number in px.

• Font design, shaping engine, hinting, variable axes, fallback fonts, ligatures, language, display density, and browser rounding can change rendered text measurements.
• Font Size Pixels must be at least 0.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

Measure the final shaped text in the target renderer and test the actual fonts, languages, viewport sizes, and accessibility settings used in production.

• Letter Spacing Points From Tracking

  Letter spacing in points from tracking in thousandths of an em and font size in points.

• 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.