Pixel Converter

Divide the pixel value by the root font size (usually 16px). So 24px ÷ 16 = 1.5rem. The rem unit is relative to the root element's font size, which defaults to 16px in most browsers unless overridden. This converter lets you set a custom root font size if your project uses a different base.

rem (root em) is relative to the root element's font size — it stays consistent across the entire document. em is relative to the current element's font size, which can cascade and compound: a child element inside a parent with font-size: 1.5em will have em calculated from that 1.5× value, causing unexpected sizes.

Use rem for font sizes and spacing to respect user browser settings — if a user increases their base font size for accessibility, rem-based layouts scale accordingly. Use px for things that should never scale with font size, like borders, specific icon sizes, or decorative element dimensions.

vh (viewport height) and vw (viewport width) are relative to the browser viewport size. 1vh = 1% of the viewport height; 100vh = the full height. They're useful for full-screen sections, hero images, and responsive layouts. Note: on mobile browsers, 100vh can be tricky because the browser chrome (address bar) affects the viewport height.

Percentage (%) in CSS is relative to the parent element's size. For width/height, it's a percentage of the parent's width/height. For font-size, it's a percentage of the parent's font size. This converter lets you set the 'parent size' context to calculate percentage values accurately.