Quick converter
Type into any field — every unit in this category updates instantly.
Root font-size 16px
Common em → % values
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Convert 2.5em to other units
Formula
rem = px ÷ root-font-size and px = rem × root-font-size. Browsers default the root font-size to 16px, so 1rem normally equals 16px unless the page (or the user's browser settings) changes it.
em works the same way, but relative to the parent element's font-size rather than the root — the numbers only match rem when nothing in the ancestor chain has resized the font.
pt is a print unit: 1pt = 1.333px, based on the fixed 96px-per-inch / 72pt-per-inch relationship browsers use.
Use it in code
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