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Zach Leatherman

Get all Font Sizes in use on a Web Page

January 10, 2019 Inspired by a tweet.

While doing some testing on font hinting, I wanted an easy way to make a test page that had examples of every single font-size in use on a page. Pasting the following snippet into your DevTools console retrieves an Array of sorted font-size values in use on a page.

(function() {
let fontSizes = new Set();

document.querySelectorAll("*").forEach(function( node ) {
fontSizes.add( window.getComputedStyle( node ).getPropertyValue("font-size") );

return Array.from( fontSizes ).sort(function(a, b) {
return parseFloat(a) - parseFloat(b);

For example, this page returned:

["10.5px", "11px", "12px", "13px", "15px", "15.7368px", "16px", "16.9474px", "18.6875px", "19.2px", "21.7895px", "22.4px", "23px", "100.35px"]

⚠️ Careful if you use vw units, these are computed values only.

I’ve also filed this as a possible enhancement for GlyphHanger.

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Zach is a builder for the web with Netlify. He’s currently fixated on web fonts and static site generators. His public speaking résumé includes talks in eight different countries at events like Beyond Tellerrand, Smashing Conference, CSSConf, and The White House. He is an emeritus of Filament Group, NEJS CONF, and still helps out with NebraskaJS. Read more about Zach »

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