Online Tool Store
Font Size Converter
Convert CSS font sizes between px, pt, em, rem, and percent with an adjustable base size and live text preview. Review the result before using it.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example shown - replace with your own value. Base font size is used for em/rem/% conversions (browser default is 16px).
px
pt
em
rem
%
The quick brown fox jumps over the lazy dog
How the font size converter works
- Enter a font size value and choose the unit it's currently in.
- Set a base font size if you need em/rem/% conversions to match your project (default 16px).
- See the equivalent size in px, pt, em, rem, and % instantly, with a live text preview.
FAQ
What units does this convert between?
Pixels (px), points (pt), em, rem, and percent (%) - the units you'll most commonly see in CSS and design specs.
Why does the base font size matter?
Em, rem, and percent are all relative units - their pixel equivalent depends on a base font size. Browsers default to 16px, but you can change it to match your project's root font size.
What is the difference between em and rem?
This tool treats them the same way for conversion purposes since both scale against a base size, but in real CSS, em is relative to the parent element while rem is always relative to the root element.
How is pt converted to px?
Using the standard 96 CSS pixels per inch and 72 points per inch ratio, so 1pt equals 96/72 px (about 1.333px).
How we compare
| Feature | Online Tool Store | Manual math | Browser dev tools |
|---|---|---|---|
| All five units at once | ✓ | ✗ | ✗ |
| Live text size preview | ✓ | ✗ | ✓ |
| No code editing required | ✓ | ✓ | ✗ |
Handy for translating a designer's px spec into rem values for your CSS, or checking how a legacy pt size maps to modern units.