$ toolfu run css-units-converter
CSS Units Converter — px to rem, em, pt Online
Free CSS units converter. Convert between px, rem, em, and pt instantly. Set base font size and see all CSS unit conversions at once.
all processing runs in your browser
css-units-converter
input > value and unit
base font size (px)
px
16px
rem
1rem
em
1em
pt
12pt
Convert CSS Units — px, rem, em, pt
Modern CSS uses multiple unit systems. Pixels for precision, rem for accessibility, em for component-relative sizing, and points for print. Switching between them requires knowing the base font size and the conversion ratios.
This tool converts any value between px, rem, em, and pt using your configured base font size. Enter a value, select the source unit, and see all four conversions instantly.
Conversion reference
- 1rem = base font size in px (default 16px)
- 1em = parent font size in px (uses base as proxy)
- 1pt = 1.333px (at 96 DPI)
- All conversions update in real time as you type
$ cat FAQ.md
How are rem and em calculated?▶
Both rem and em are relative to a font size. rem is relative to the root element's font size (typically 16px). em is relative to the parent element's font size. This tool uses the base font size you configure (default 16px) for both calculations.
What's the relationship between px and pt?▶
Points (pt) are a print unit. At the standard screen resolution of 96 DPI, 1pt = 1.333px (or 96/72). This tool uses this standard conversion ratio.
Why would I use rem instead of px?▶
rem units scale with the user's browser font size settings, making your layout more accessible. If a user increases their default font size, rem-based layouts adjust proportionally while px-based layouts stay fixed.