4 rem to px = 64px
4 rem equals 64 pixels at the default root font size of 16px. Adjust the root size below to recalculate.
What’s 4rem used for?
4rem (64px at default root) is a display-size font value or oversized spacing token — used for hero headlines on landing pages, large display type, and the most generous gaps in well-spaced layouts. Tailwind's text-6xl and spacing-16 both land at 64px.
How it works
To convert 4rem to pixels, multiply by the root font size: 4 × 16 = 64. The rem unit is relative to the root element’s font size, which browsers default to 16px.
4rem at different root sizes
If you’ve overridden the html root font size, the pixel equivalent of 4rem shifts. Here’s 4rem at common root sizes.
| Root size | 4rem in px |
|---|---|
| 16px (default) | 64px |
| 12px | 48px |
| 14px | 56px |
| 18px | 72px |
| 20px | 80px |
| 24px | 96px |
4rem in CSS
Use 4rem as generous section padding on a landing-page block.
.section {
padding-block: 4rem; /* 64px */
}FAQ
Is 4rem the same as 64px?
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 4rem at other root sizes.
Why use 4rem instead of 64px?
Because 4rem scales with the user’s browser font-size preference, and 64px does not. If a user enlarges their default font size for accessibility, anything sized in rem scales proportionately — including this value. Use rem for type and type-adjacent properties; reach for px only when the value must stay fixed regardless of user settings.