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// CSS / Design

PX to REM online

Convert pixel values to rem units for responsive CSS design

PX to REM Converter logo
by
CHUNKY
MUNSTER
// Common conversions at 16px base

How to Use the PX to REM Converter

  1. Paste or enter your input into the text field.
  2. Configure any options (format, delimiter, encoding, or mode) using the controls above the output.
  3. The result updates instantly — no submit button required for most operations.
  4. Click Copy or Download to take the output to your next step.

rem stands for "root em" — every rem value is multiplied by the root element's font-size to produce a pixel value. Designing in rem instead of px means user zoom and accessibility settings scale your layout proportionally, instead of leaving large pixel-fixed components stranded next to scaled body text.

How the PX to REM Converter Works

The conversion is plain division: rem = pixels / base. Slide the base font-size between 10 and 24 px and the page recomputes both the headline value and a quick reference table of common pixel sizes. The "10 px base" trick (set { font-size: 62.5% }) gives the cleanest mental math — every 10 px becomes exactly 1 rem.

Frequently Asked Questions

What is the difference between rem and em?

em is relative to the parent element's font-size; rem is always relative to the root () font-size. rem keeps spacing predictable across nested components, which is why it is preferred for layout sizes.

Why is the default base 16 px?

Browsers ship with a 16 px default font-size on . Building a design around that base means user font-size preferences (zoom, accessibility settings) scale your whole layout proportionally — a key accessibility win over fixed-pixel layouts.

Should I really use rem for everything?

Use rem for font sizes, line-heights, and layout spacing where user-zoom respect matters. Keep px for borders, fine details, and 1-pixel hairlines where exact rendering matters more than scaling. Mix the two on purpose, not by accident.

My result has long decimals — is that OK?

Yes. Browsers handle fractional rem values fine and rounding tiny pixel differences is rarely visible. If you prefer round numbers, set a base that divides cleanly (10 px gives you a tidy 1 rem = 10 px).

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