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Developer units

REM to PX Converter

Translate rem values into pixel equivalents for design handoff, inspection, and debugging. Change the default 16px root size to match your stylesheet.

Instant resultAdjustable assumptionsNo data sent
Instant conversion

rem px

Runs in your browser
pixels16px

Result rounded to a maximum of six decimal places.

Conversion rulepx = rem × root font size

At a 16px root: px = rem × 16.

01
Method

How to convert root ems to pixels

Multiply the rem value by the root element's font size. If the root font size is 16px, 1rem equals 16px and 1.5rem equals 24px.

Formulapx = rem × root font size

At a 16px root: px = rem × 16.

02
Worked example

Convert 1.5 rem to px

Apply the conversion rule to 1.5 root ems. Using the default settings, the result is 24 px.

1.5 rem24 px

Default context: root font size 16px.

03
Quick reference

rem to px conversion table

These pre-calculated values use the same formula and default settings as the converter above.

Common root ems to pixels conversions
root ems (rem)pixels (px)
0.125 rem2 px
0.25 rem4 px
0.5 rem8 px
0.75 rem12 px
1 rem16 px
1.125 rem18 px
1.25 rem20 px
1.5 rem24 px
2 rem32 px
2.5 rem40 px
3 rem48 px
4 rem64 px
5 rem80 px
6 rem96 px
04
Practical use

Code and calculation snippets

Reuse the same conversion in a stylesheet or application. Keep contextual font sizes configurable when working with relative CSS units.

CSS
html { font-size: 16px; }
.heading { font-size: 1.5rem; } /* 24px */
JavaScript
const pixels = rem * rootFontSize;
Sass
@function px($rem, $base: 16) {
  @return $rem * $base * 1px;
}
05
Interpretation

Using the result accurately

Use the computed font size of the HTML element, not a component's local font size. This keeps the conversion aligned with how rem is resolved by CSS.

Important limitation

A rem value has no single pixel equivalent until the root font size is known. Project resets, accessibility settings, and responsive CSS can change that context.

Reference: W3C CSS Values and Units: font-relative lengths.

Common questions

REM to PX Converter FAQ

Short answers about the formula, assumptions, and displayed precision.

How do I convert root ems to pixels?

Multiply the rem value by the root element's font size. If the root font size is 16px, 1rem equals 16px and 1.5rem equals 24px. For example, 1.5 rem converts to 24 px using the default settings.

What formula does this rem-to-px converter use?

px = rem × root font size. At a 16px root: px = rem × 16.

What assumptions does the calculator make?

The calculator starts with 16px for the root font size. You can change it to match your CSS.

How many decimal places should I use?

The calculator shows up to six decimal places and removes unnecessary trailing zeros. Keep more precision for further calculations, then round the final value to suit your measurement or design system.