CSS px ↔ rem ↔ em Converter

Convert CSS units between pixels, rem, em and points (assuming the default 16px root font size).

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CSS px / rem / em Converter

Design • CSS units

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Enter a value to convert

How to Use the CSS px / rem / em Converter

  1. Enter a value — type any number. Invalid text and symbols are blocked automatically.
  2. Select From and To units — choose the units to convert between.
  3. Read the animated result — the converted value, factor, and full reference table update instantly.
  4. Use Swap (⇄) — reverse the conversion in one click.

Why Use This CSS px / rem / em Converter

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Accurate Standards

Built on internationally recognised SI and standards-body conversion factors for dependable results.

Instant & Animated

Results update live as you type, with a clear visual breakdown across every unit at once.

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100% Private

Everything runs in your browser — no account, no uploads, nothing leaves your device.

Understanding the CSS px / rem / em Converter

Modern responsive web design mixes CSS units: pixels (px) are fixed, while rem and em scale with font size (1 rem = 16px by default). Converting between px, rem, em and points keeps typography and spacing consistent and accessible across devices.

Front-end developers use this to translate a designer's pixel values into scalable rem/em. Enter any value to see the equivalents, assuming the standard 16px root font size.

Common CSS px / rem / em Converter Values

Quick reference — 1 Pixels (px) is equal to:

Root emrem0.0625
Emem0.0625
Pointspt0.750000019

CSS px / rem / em Converter FAQ

With the default browser root font size of 16px, 1 rem = 16px. So 1.5rem = 24px. Change the root size and rem scales with it.

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✔ Reviewed by the True Value Calc editorial team🗓 Last updated June 2026📚 Sources: NIST, BIPM SI unit definitions