At the default root font size of 16px, 3rem is exactly 48px.
Calculation based on a root font-size of 16 pixels.
How to convert 3rem to px
To convert rem to pixels, multiply the rem value by the root font size: px = rem × 16. For 3rem that is 3 × 16 = 48px.
48px is a large size, common for headings, section padding and generous layout gaps. It is often used for display headings and big layout gaps.
3rem at different root font sizes
| Root font size | Input | Result |
|---|---|---|
| 10px | 3rem | 30px |
| 12px | 3rem | 36px |
| 14px | 3rem | 42px |
| 15px | 3rem | 45px |
| 16px | 3rem | 48px |
| 18px | 3rem | 54px |
| 20px | 3rem | 60px |
| 22px | 3rem | 66px |
| 24px | 3rem | 72px |
CSS examples
font-size: 3rem; /* 48px */
padding: 3rem;
margin-bottom: 3rem;
width: 3rem;The same values in pixels, if you need a fixed size:
font-size: 48px;
padding: 48px;Tailwind CSS equivalent
The default spacing scale has a step for 3rem: use classes like p-12, m-12, gap-12, w-12 and h-12. As a font size, 3rem is the default text-5xl class.
Nearby values
Frequently Asked Questions
3rem equals 48px when the root font size is the browser default of 16px. The calculation is 3 × 16 = 48.
48px equals 3rem at a 16px root font size (48 ÷ 16 = 3).
Yes. rem is relative to the root font size, so 3rem becomes 54px at an 18px root and 60px at a 20px root. 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.