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REM to Percent Converter

Convert REM values to CSS percent. 1rem = 100%, 1.5rem = 150%, 0.75rem = 75% — direct multiplication by 100.

Last updated: May 21, 2026

Client-Side Processing
Input Data Stays on Device
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What is REM to Percent Converter?

REM is relative to the root (`html`) element's font size. When the root font size is 16px (the browser default), 1rem = 16px. Percent, when applied to font-size on a root-level element, is also relative to the root. So numerically, 1rem = 100% of the root size.

The conversion is: **% = rem × 100**. This is useful when mixing rem and percent values in a design system or when rewriting stylesheet declarations.

How to Use REM to Percent Converter

1

Enter one or more REM values (comma or newline separated)

2

Copy the percent output or use the reference table

3

The formula is always: % = rem × 100

Common Use Cases

  • Developers converting REM type scales to percent for compatibility with older browsers.
  • Teams comparing rem and percent values in a shared design token system.
  • Front-end engineers rewriting rem-based utility classes to percent variants.
  • Students learning the numerical relationship between rem and percent in CSS.

Example Input and Output

Convert common REM values to their percentage equivalents.

REM values
0.75
1
1.25
1.5
Percent output
0.75rem → 75%
1rem → 100%
1.25rem → 125%
1.5rem → 150%

Privacy

All conversions run in your browser. No data is sent to any server.

Frequently Asked Questions

Is rem to percent always just multiplying by 100?
Numerically, yes — 1rem = 100% is always the ratio. However, rem is relative to the root element's font size, while percent for font-size is relative to the parent. On the root element itself they're the same; on nested elements, percent cascades while rem stays constant.

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