Neuctra Tools Logo
Neuctra ToolsDeveloper Utilities
Developer Tools

CSS Unit Converter

Convert between px, rem, em, percent, and pt instantly. This css unit converter online updates every field live as you type, using your chosen base font size.

The browser default root font size is 16px.

Relative to the parent element, not always equal to rem.

Advertisement

About the CSS Unit Converter

This css unit converter online tool converts between pixels, rems, ems, percentages, and points the moment you type. Whether you are translating a legacy design that used fixed pixel values into a responsive rem-based system, or checking what a percentage font size actually renders as on screen, every field stays in sync using your chosen base font size as the common reference point.

All five units route through pixels internally: a px to rem converter divides by the base font size, a rem to px calculator multiplies by it, percent is the same ratio expressed out of 100, and points follow the fixed 96px-per-inch, 72pt-per-inch relationship used by CSS. The field you are actively typing into is never overwritten, so you can keep typing without the value jumping around.

Advertisement

How to Use

  1. Set the Base Font Sizeto match your project's root font size, or leave it at the 16px browser default.
  2. Type a value into any of the px, rem, em, percent, or pt fields.
  3. Watch the remaining fields update automatically to the equivalent value.
  4. Copy the converted value you need directly into your stylesheet.

Quick Reference at 16px Base

Common equivalents when the base font size is the browser default of 16px.

pxremem%pt
8px0.5rem0.5em50%6pt
12px0.75rem0.75em75%9pt
16px1rem1em100%12pt
20px1.25rem1.25em125%15pt
24px1.5rem1.5em150%18pt
32px2rem2em200%24pt
Advertisement

Who Should Use This Tool

  • Frontend developers converting fixed pixel designs into a rem-based responsive layout.
  • UI designers who need a quick rem to px calculator when handing off specs to engineers.
  • Accessibility engineerschecking that text scales correctly relative to a user's browser font size settings.
  • Students learning CSS who want to see exactly how px, em, rem, percent, and pt relate to one another.

Privacy first. All conversions run directly in your browser using plain JavaScript arithmetic. Nothing you type is ever uploaded, logged, or stored on a server.

Type a value into any field, px, rem, em, percent, or pt, and the css unit converter online instantly recalculates the rest. Adjust the base font size first if your project uses something other than the 16px browser default.
A px to rem converter divides the pixel value by the root element's font size, which is 16px by default in most browsers. So 16px becomes 1rem, 24px becomes 1.5rem, and so on at the default base size.
Yes, this em to px converter free tool has no limits, no account, and no watermark. It multiplies your em value by the relevant font size to return an accurate pixel equivalent instantly.
No, em and rem are not always the same, even though this rem to px calculator treats them numerically alike at the root level. Rem is always relative to the root element's font size, while em is relative to its own parent element, which can differ inside nested components.
Pixels are a fixed screen unit, points are a print-based unit equal to 1.333px at 96 DPI, and percent is relative to a base font size, typically the root or parent element. This css px em rem converter handles all four conversions plus points in one place.