Firefox Browser Add-ons
  • Extensions
  • Themes
    • for Firefox
    • Dictionaries & Language Packs
    • Other Browser Sites
    • Add-ons for Android
Log in
Preview of PX to REM Converter

PX to REM Converter by Markeir

Instantly convert pixel values to REM with a custom base font size. Fast, clean, and built for developers. No ads, no tracking.

0 (0 reviews)0 (0 reviews)
1 User1 User
Download Firefox and get the extension
Download file

Extension Metadata

Screenshots
About this extension
Instantly convert pixel values to REM with a custom base font size. Fast, clean, and built for developers. No ads, no tracking.

PX to REM Converter — your developer toolbar shortcut for instant CSS unit conversion.

Stop the mental gymnastics. Click the icon, type a pixel value, and instantly see the REM equivalent — right from your Chrome toolbar.

⚡ What it does

Type any pixel value and the extension immediately shows you the exact REM equivalent based on your configured root font size. The default is 16px — matching the browser — but you can set your project's actual base and it's remembered automatically.

🛠 Features
  • Real-time conversion — result updates as you type
  • Configurable root font size (10px, 16px, 18px — your call)
  • Quick-pick buttons for common values like 8, 12, 16, 24, 32
  • Reference table with 20 pre-calculated PX/REM pairs
  • One-click copy to clipboard
  • Formula display so you always see the math
  • Works fully offline — no internet ever needed

🔒 Zero data collection. No analytics, no tracking, no network requests, no ads — ever. The only permission used is storage, to remember your root font size locally.
Rated 0 by 0 reviewers
Sign in to rate this extension
There are no ratings yet

Star rating saved

5
0
4
0
3
0
2
0
1
0
No reviews yet
Permissions and data

Data collection:

  • The developer says this extension doesn't require data collection.
Learn more
More information
Add-on Links
  • Support site
  • Support Email
  • Copy add-on ID
Version
1.0.0
Size
16.93 KB
Last updated
2 months ago (Apr 21, 2026)
Related Categories
  • Web Development
License
All Rights Reserved
Privacy Policy
Read the privacy policy for this add-on
Version History
  • See all versions
Add to collection
Report this add-on
Go to Mozilla’s homepage

Add-ons

  • About
  • Firefox Add-ons Blog
  • Extension Workshop
  • Developer Hub
  • Developer Policies
  • Community Blog
  • Forum
  • Report a bug
  • Review Guide

Browsers

  • Desktop
  • Mobile
  • Enterprise

Products

  • Browsers
  • VPN
  • Relay
  • Monitor
  • Pocket
  • Bluesky (@firefox.com)
  • Instagram (Firefox)
  • YouTube (firefoxchannel)
  • Privacy
  • Cookies
  • Legal

Except where otherwise noted, content on this site is licensed under the Creative Commons Attribution Share-Alike License v3.0 or any later version.