REM to PX
Convert rem to px โ instantly in your browser, nothing uploaded.
Convert a whole CSS block
Sizing in px is sometimes needed when a design tool or email client does not understand rem. This free rem-to-px converter does the maths against your root font size (16px by default) and can also rewrite an entire CSS block at once, replacing every rem value with its px equivalent. It all runs in your browser, so nothing is uploaded, and it works offline once loaded.
Frequently Asked Questions
How do I convert rem to px?
Type a value into the box above and the converted result appears immediately, using the root font size you set (16px is the browser default). To convert many values at once, paste a whole CSS block into the second box and every rem value is rewritten to px automatically.
What is the formula?
px = rem ร root font size. With the default 16px root, 1.5rem becomes 24px. If your project sets a different root font size, change the base field and everything recalculates.
Why use px?
px is absolute and predictable, which is what you want for hairline borders, and it is required by tools and email clients that do not support rem.
Does it change 0 values or values inside other units?
Zero stays as plain 0 (no unit needed), and only rem values are touched โ percentages, viewport units and other lengths are left exactly as they are. Your CSS structure, comments and formatting are preserved.
Is it free and private?
Yes. It is completely free with no signup, and the conversion is simple arithmetic done in your browser โ nothing is uploaded and it works offline once the page has loaded.