At the default root font size of 16px, 3px is exactly 0.1875rem.
Calculation based on a root font-size of 16 pixels.
How to convert 3px to rem
To convert pixels to rem, divide the pixel value by the root font size: rem = px ÷ 16. For 3px that is 3 ÷ 16 = 0.1875rem.
3px is a very small size, typically used for borders, hairlines, icon gaps and fine detail.
3px at different root font sizes
| Root font size | Input | Result |
|---|---|---|
| 10px | 3px | 0.3rem |
| 12px | 3px | 0.25rem |
| 14px | 3px | 0.2143rem |
| 15px | 3px | 0.2rem |
| 16px | 3px | 0.1875rem |
| 18px | 3px | 0.1667rem |
| 20px | 3px | 0.15rem |
| 22px | 3px | 0.1364rem |
| 24px | 3px | 0.125rem |
CSS examples
font-size: 0.1875rem; /* 3px */
padding: 0.1875rem;
margin-bottom: 0.1875rem;
width: 0.1875rem;The same values in pixels, if you need a fixed size:
font-size: 3px;
padding: 3px;Tailwind CSS equivalent
0.1875rem is not part of the default Tailwind scale, but you can use an arbitrary value such as p-[0.1875rem] or text-[0.1875rem].
Nearby values
Frequently Asked Questions
3px equals 0.1875rem when the root font size is the browser default of 16px. The calculation is 3 ÷ 16 = 0.1875.
0.1875rem equals 3px at a 16px root font size (0.1875 × 16 = 3).
Yes. If the root font size is 18px, 3px equals 0.1667rem, and at 20px it equals 0.15rem. 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.