At the default root font size of 16px, 13px is exactly 0.8125rem.
Calculation based on a root font-size of 16 pixels.
How to convert 13px to rem
To convert pixels to rem, divide the pixel value by the root font size: rem = px ÷ 16. For 13px that is 13 ÷ 16 = 0.8125rem.
13px is a small size, common for captions, labels, small text and tight spacing.
13px at different root font sizes
| Root font size | Input | Result |
|---|---|---|
| 10px | 13px | 1.3rem |
| 12px | 13px | 1.0833rem |
| 14px | 13px | 0.9286rem |
| 15px | 13px | 0.8667rem |
| 16px | 13px | 0.8125rem |
| 18px | 13px | 0.7222rem |
| 20px | 13px | 0.65rem |
| 22px | 13px | 0.5909rem |
| 24px | 13px | 0.5417rem |
CSS examples
font-size: 0.8125rem; /* 13px */
padding: 0.8125rem;
margin-bottom: 0.8125rem;
width: 0.8125rem;The same values in pixels, if you need a fixed size:
font-size: 13px;
padding: 13px;Tailwind CSS equivalent
0.8125rem is not part of the default Tailwind scale, but you can use an arbitrary value such as p-[0.8125rem] or text-[0.8125rem].
Nearby values
Frequently Asked Questions
13px equals 0.8125rem when the root font size is the browser default of 16px. The calculation is 13 ÷ 16 = 0.8125.
0.8125rem equals 13px at a 16px root font size (0.8125 × 16 = 13).
Yes. If the root font size is 18px, 13px equals 0.7222rem, and at 20px it equals 0.65rem. The pixel value itself never changes, only the rem equivalent. Use the base font size field above to try any value.
Prefer rem for font sizes, spacing and layout so they respect the user's browser font settings and scale for accessibility. Use px for details that should never scale, such as 1px borders or fixed icon sizes.