REM & EM to PX Converter

Convert pixels into rem, em, and percent values with custom root and parent font sizes for CSS work.

Convert PX to REM and EM

Enter a pixel value and adjust the root or parent size to generate CSS-ready units.

Pixels Root size Parent size

REM value

1.5rem

Relative to root font size.

EM value

1.5em

Relative to parent font size.

Percent

150%

Original pixels

24px

CSS example

.element {
  font-size: 1.5rem;
  padding: 1.5em;
}

With the common browser default of 16px root size, 1rem equals 16px.

REM is relative to the root element font size, while EM is relative to the current or parent font size.

Use rem for scalable typography and spacing, and px for precise fixed details when needed.

Nested elements can inherit changed font sizes, so em-based values can multiply across component levels.

Content cluster

Use these supporting guides to understand the tool result and next testing steps.