Font Size Converter
Convert CSS font sizes between px, rem, em, pt, vw, and percentage. Set your root/base font size for accurate em/rem conversions.
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Frequently Asked Questions
What is the difference between px, em, and rem?
px is an absolute pixel value. em is relative to the current element's font size (1em = 100% of parent). rem is relative to the root (html) element font size — typically 16px. rem is recommended for accessible, scalable typography.
What is the default browser font size?
Most browsers default to 16px. This means 1rem = 16px, 1em (from root) = 16px, and 1.5rem = 24px in a default environment.
When should I use pt instead of px?
pt (points) is a print unit — 1pt = 1/72 inch. Use pt for print stylesheets (@media print). For screen design, use px, rem, or em instead.