10px to rem = 0.625rem
10 pixels equals 0.625rem at the default root font size of 16px. Adjust the root size below to recalculate.
What’s 10px used for?
10px is the smallest font size still considered readable in production interfaces — used for legal disclaimers, image captions, dense data tables, and tiny status indicators. At 16px root it's 0.625rem. Many design systems treat 10px as the floor below which accessibility starts to fail; it should rarely be used for body content.
How it works
To convert 10px to rem, divide by the root font size: 10 / 16 = 0.625. The rem unit is relative to the root element’s font size, which browsers default to 16px.
10px to rem at different root sizes
If you’ve overridden the html root font size, the rem equivalent of 10px shifts. Here’s 10px at common root sizes.
| Root size | 10px in rem |
|---|---|
| 16px (default) | 0.625rem |
| 12px | 0.8333rem |
| 14px | 0.7143rem |
| 18px | 0.5556rem |
| 20px | 0.5rem |
| 24px | 0.4167rem |
10px in CSS
Use 10px for captions, labels, or very small interface text.
.caption {
font-size: 10px; /* 0.625rem */
letter-spacing: 0.02em;
text-transform: uppercase;
}FAQ
Is 10px the same as 0.625rem?
Yes, at the browser default root font size of 16px. If the root has been changed (some sites use html { font-size: 62.5% } or similar), the conversion changes — see the table above for 10px at other root sizes.
Will 10px scale with user font preferences?
No. Pixel values are absolute and ignore the user’s browser font-size preference. If you want 10px to scale when users enlarge their default font size, use 0.625rem instead — same visual size at the default root, but it grows or shrinks with the user’s setting.