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Open toolPX to REM Converter
Convert a pixel value into CSS rem units using your root font size. Review the conversion and a small reference table for common pixel values.
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How PX to REM Converter works
A pixel value is divided by the entered root font size.
The pixel value is divided by the entered root font size to produce rem. The same denominator is applied to the reference-table values; actual rendering still depends on the computed font size of the html element.
The common 16 px root is a default, not a guarantee. Check the actual computed root font size in your CSS.
How to use PX to REM Converter
The root font size defines what the converted rem value means in a particular stylesheet.
Enter pixels and the root size
Enter the pixel value and a positive root font size in pixels. Use the target page’s root size if you know it, rather than assuming the default value applies. The converter does not inspect or update another website’s styles.
Pixel value
Calculate the rem value
Select Calculate and read the CSS rem value. The page divides the entered pixels by the root size and formats the result to four decimal places. This changes unit notation; actual rendering still depends on the target document’s computed root font size.
1.2 rem
Review the shared reference scale
Check Pixels, Root font size, and the common-size reference table. Each table value uses the same entered root size. Test a converted value in the target layout before assuming it reproduces an intended spacing or text size across contexts.
Output details
Convert pixels to rem for CSS spacing and scales
Keep the root assumption with converted lengths when sharing them with another developer.
Convert CSS spacing from pixels to rem
A hypothetical twenty four pixel spacing value with a sixteen pixel root becomes 1.5 rem. Put the converted value into the intended CSS property yourself. The page does not rewrite stylesheets or inspect the computed layout of a website.
Prepare a scale of lengths
Use the reference table to compare common pixel values under one root setting. Change the root and the whole table uses the new basis. This makes it easier to keep a conversion sheet internally consistent without calculating each listed value separately.
Review a nondefault root
Enter a root size that matches your target page, then repeat the conversion. A different root can produce a different numerical rem value for the same pixels. Confirm the computed html font size before comparing conversions from different projects.
PX to REM values depend on the root font size
Read the conversion as a ratio that depends on the target root size.
The main result is rounded to four decimal places for display. Each reference row also uses the entered root size. The output is a unit conversion and does not guarantee the same visible size under a different root.
A rem value is a length relative to the root font size. This page does not calculate em units, whose reference can differ, or account for responsive style changes in the surrounding document.
Check CSS context after conversion
Confirm the computed root size and test the value in the target layout.
A zero root cannot define the conversion. Enter a positive computed root size and keep units out of the numeric fields. If a rendered element looks different, check the actual root and applicable CSS rules in that page.
This tool presents the value and a reference table. It does not provide a stylesheet upload, a batch CSS rewrite or a generated CSS download. Use the result in your own declaration and verify the component in context.
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Open toolUse PX to REM Converter
Convert a pixel value into CSS rem units using your root font size.
PX to REM Converter: common questions
Answers about using PX to REM Converter and understanding its results.
What is 1 rem?
One rem equals the computed font size of the root html element.
Can I change the base size?
Yes. Enter the root font size used by your project.
Does this inspect my website’s font size?
No. Enter the root font size yourself. The page does not read styles from another website.
Will this automatically make a design responsive?
No. It provides a unit conversion. How rem values behave depends on the root font size and the styles in the receiving layout.