What CSS units does this converter support?

It supports px, rem, em, vw, vh, %, and pt — the most commonly used CSS units for web development.

How does rem conversion work?

rem is relative to the root element's font size. By default, browsers use 16px. You can customize the base font size in the settings to match your project.

What is the difference between em and rem?

rem is relative to the root (html) font size, while em is relative to the parent element's font size. This tool lets you set both independently for accurate conversions.

Do I need to sign up to use this tool?

No — CSS Unit Converter runs entirely in your browser with no login, no API calls, and no data stored. It's free and instant.

Free Developer Tool

Convert CSS Units
Instantly & Accurately

Switch between px, rem, em, vw, vh, %, and pt with customizable base font size and viewport dimensions. No signup, no API — runs entirely in your browser.

🔄

7 Units Supported

Convert between px, rem, em, vw, vh, %, and pt seamlessly.

⚡

Real-Time Results

See conversions update instantly as you type — zero latency.

📐

Custom Context

Set your own base font size, parent font size, and viewport dimensions for accurate conversions.

Input

Quick Reference

1rem = 16px (root font size)

1em = 16px (parent font size)

1vw = 19.2px (viewport: 1920px)

1vh = 10.8px (viewport: 1080px)

1% = 19.2px (parent: 1920px)

1pt = 1.3333px (96 DPI)

Frequently Asked Questions

Everything you need to know about CSS Unit Converter.

Convert CSS UnitsInstantly & Accurately