Ratio and aspect ratio
Ratio and aspect ratio lets you reduce integer ratios and inspect aspect ratios in your browser.
CSS unit converter
CSS unit converter lets you convert px, rem, em, vw, and vh with explicit font and viewport assumptions in your browser.
CSS unit converter
⌂ Inputs and results stay in this browser and are not automatically stored or sent.
Waiting for input
Input & settings
Output
Waiting for input
Complete text result
How to use
Choose source/target units and provide the applicable root font size, element font basis, and viewport dimensions.
16 px is not always 1 rem. The tool does not read your site's CSS; verify computed styles and enlarged-text behavior on the actual page.
Examples
16Principles and limits
Each input is limited to 1,048,576 bytes, output to 33,554,432 bytes, and processing to 5,000 ms. Input is never silently truncated.
Guides
Related tools
Flexbox and Grid generator
Flexbox and Grid generator lets you generate and preview Flexbox or Grid layout CSS in your browser.