Skip to content
Tools.Town
290+ free online tools

px ↔ rem Converter

100% Free

Convert CSS pixels to rem (and back) with a custom root font size.

100% Secure
No Sign Up
Client-Side
Be the first to rate

Converted

1rem

16px = 1rem (root 16px)

Embed This Tool

Easy to Embed

Add px ↔ rem Converter to your website or blog in seconds.

  • Responsive design
  • Lightweight & fast
  • No backend required
  • Always up-to-date 
<iframe
  src="https://tools.town/embed/px-rem-converter/"
  width="100%"
  height="600"
  style="border:none; border-radius:12px;"
  loading="lazy"
  title="px ↔ rem Converter">
</iframe>

Share This Tool

Share Instantly

Share px ↔ rem Converter with anyone — no login required.

  • Shareable link
  • No login required
  • Works on any device
  • No account needed

Share via

Advertisement

How to Use

  1. 1 Choose px → rem or rem → px
  2. 2 Enter the value
  3. 3 Set root font size (default 16)
  4. 4 Copy the converted unit into CSS

Features

  • Both directions
  • Custom root px
  • 4-decimal rem precision
  • Live conversion
  • Client-side

Why it Matters

Design handoffs still quote px while codebases prefer rem. A one-field converter removes the mental divide-by-16 loop.

★★★★★

Convert between px and rem using your root font size (default 16px).

Frequently Asked Questions

Why root 16?
Browser default. Match your html { font-size } if different.
em units?
em is relative to parent — rem is relative to root. This tool is rem-focused.
Subpixels?
Rem values round to 4 decimals for CSS friendliness.
📖

Want to understand the math?

Browse all guides →
Web Config Ops
subnet

Web Config Ops — Subnets, Permissions, HTTP Status & CSS Units

Hub for Tools.Town server and web config math: IPv4 CIDR subnetting, chmod permission modes, HTTP status code lookup, and px ↔ rem conversion — free, in-browser.

16 Aug 2026

5 min read

Related Tools You Might Like

Aspect Ratio Calculator

Find the aspect ratio of any size and resize images while keeping the same proportions.

Type Scale Generator

Generate a modular CSS typography scale — choose a ratio, base size, and unit to get CSS custom properties and a Tailwind fontSize config.

Unit Converter

Convert between length, weight, volume, area, and speed units — metric and imperial — instantly.

Border Radius Generator

Visually craft CSS border-radius with per-corner sliders, live preview, unit toggle (px/em/rem/%), and shorthand collapsing.

Box Shadow Generator

Visually craft CSS box-shadow — offset, blur, spread, color, opacity, inset toggle, plus Material-style elevation presets.

Browse more free tools
More Design Tools All categories