What does this tool do?
A rem is relative to the root element font size, which is 16 pixels by default in browsers but can be changed by the user or by CSS. This converter keeps the arithmetic straight in both directions.
The Formula
Pixels = rem × root font size; rem = pixels ÷ root font sizeFrequently Asked Questions
Should I use rem or px in CSS?
rem scales with the user font-size setting and is generally better for text, spacing and layout. Pixels are still useful for borders, hairlines and fixed media queries.
Why does 1 rem not equal 16 px on my site?
The root font size has been overridden, either by a CSS rule on the html element or by browser accessibility settings. Enter the actual value to get the right conversion.