Toolzie

CSS Unit Converter

Convert between px, rem, and pt based on a root font size.

Assumes 96 pixels per inch (common web standard for pt conversion).

How to Use the CSS Unit Converter

Enter value and source unit. Pick target unit, set base size if needed. Conversion instant.

Modern CSS has many units; converting between px and rem constantly. Tool handles math.

Frequently Asked Questions

Rem vs em?

Rem: root size (predictable); em: parent size.

rem vs px?

Rem respects browser font settings, improving accessibility.

Base font?

Default 16px, customizable.

vw/vh?

1vw=1% viewport width; used for responsive.

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About This Tool

Convert between CSS units — px, em, rem, vw, vh, pt, and more — with the Toolzie CSS Unit Converter. Set your base font size and viewport dimensions for accurate em and rem conversions relevant to your project.

How to Use

  1. Enter the value you want to convert.
  2. Select the source unit (e.g. px).
  3. Select the target unit (e.g. rem).
  4. Set your root font size if converting to/from em or rem.

Frequently Asked Questions

What is the difference between em and rem?

em is relative to the parent element's font size. rem is relative to the root (html) element's font size — typically 16px by default.

What root font size should I use?

Most browsers default to 16px. If your CSS sets html { font-size: 62.5%; }, your rem base is 10px.

When should I use vw/vh?

vw (viewport width) and vh (viewport height) are great for responsive typography and full-screen layouts.

Can I convert pt to px?

Yes — 1pt = 1.333px at 96dpi, which is the standard screen resolution.