Browser

KaTeX supports all major browsers, including Chrome, Safari, Firefox, Opera, and Edge.

Starter template

<!DOCTYPE html>
<!-- KaTeX requires the use of the HTML5 doctype. Without it, KaTeX may not render properly -->
<html>
  <head>
    <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.min.css" integrity="sha384-vlBdW0r3AcZO/HboRPznQNowvexd3fY8qHOWkBi5q7KGgqJ+F48+DceybYmrVbmB" crossorigin="anonymous">

    <!-- The loading of KaTeX is deferred to speed up page rendering -->
    <script defer src="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.min.js" integrity="sha384-AtrdNsnxl/75rvBneBVH7DtOvCxSVahR2zWqle1coBKd8DEmLoviqNeJSx64gNAs" crossorigin="anonymous"></script>

    <!-- To automatically render math in text elements, include the auto-render extension: -->
    <script defer src="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/contrib/auto-render.min.js" integrity="sha384-bjyGPfbij8/NDKJhSGZNP/khQVgtHUE5exjm4Ydllo42FwIgYsdLO2lXGmRBf5Mz" crossorigin="anonymous"
        onload="renderMathInElement(document.body);"></script>
  </head>
  ...
</html>

Loading as Global

If you include the katex.js directly, the katex object will be available as a global variable.

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.css" integrity="sha384-xo3oXcu2FwjgZEcZnpFAF2BUCgyAPNcn8CwwPnaN0ajcbe0WxSoeKnFeeAfQnIZD" crossorigin="anonymous">
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.js" integrity="sha384-ZQXoYllNtmeIZKmaU4jDNeTAe8gbbfWsxATRIwJ6zFmlwUpNHuZn8Hsqf8QCa647" crossorigin="anonymous"></script>

KaTeX also provides minified versions:

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.min.css" integrity="sha384-vlBdW0r3AcZO/HboRPznQNowvexd3fY8qHOWkBi5q7KGgqJ+F48+DceybYmrVbmB" crossorigin="anonymous">
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.min.js" integrity="sha384-AtrdNsnxl/75rvBneBVH7DtOvCxSVahR2zWqle1coBKd8DEmLoviqNeJSx64gNAs" crossorigin="anonymous"></script>

The examples above load the script deferred using the defer attribute to speed up page rendering. The katex object will be available after DOMContentLoaded event is fired on the document. If you do not use defer, katex object will be available after the corresponding script tag.

If KaTeX is not used immediately or not critical, it is possible to load KaTeX asynchronously. Add async attribute to script and use rel="preload" and onload attribute on link.

By default, KaTeX fonts use font-display: block to prevent Flash of Unstyled Text (FOUT). If you would rather use font-display: swap to prevent Flash of Invisible Text (FOIT), include katex-swap.css or katex-swap.min.css:

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex-swap.min.css" integrity="sha384-ZLYhxmRv7L3uIzPeM2/QcB1VDGw0KWFqt0YK5lX+8+ju3nl/Dx+HV5dl06SUiJ6E" crossorigin="anonymous">

To prevent both FOUT and FOIT, you can prefetch KaTeX fonts. Use Font Loading API or Web Font Loader:

<script>
  window.WebFontConfig = {
    custom: {
      families: ['KaTeX_AMS', 'KaTeX_Caligraphic:n4,n7', 'KaTeX_Fraktur:n4,n7',
        'KaTeX_Main:n4,n7,i4,i7', 'KaTeX_Math:i4,i7', 'KaTeX_Script',
        'KaTeX_SansSerif:n4,n7,i4', 'KaTeX_Size1', 'KaTeX_Size2', 'KaTeX_Size3',
        'KaTeX_Size4', 'KaTeX_Typewriter'],
    },
  };
</script>
<script defer src="https://cdn.jsdelivr.net/npm/webfontloader@1.6.28/webfontloader.js" integrity="sha256-4O4pS1SH31ZqrSO2A/2QJTVjTPqVe+jnYgOWUVr7EEc=" crossorigin="anonymous"></script>

You can also use rel="preload". Add <link rel="preload" href=(path to WOFF2 font) as="font" type="font/woff2" crossorigin="anonymous"> to head. Note that only few browsers support it and they all support WOFF2 so preloading WOFF2 fonts is enough.

See Google Web Fundamentals - Web Font Optimization for more detail.

Module Loaders

AMD

<script type="text/javascript">
    require([
        "https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.js",
    ], katex => {
        ...
    });
</script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.css" integrity="sha384-xo3oXcu2FwjgZEcZnpFAF2BUCgyAPNcn8CwwPnaN0ajcbe0WxSoeKnFeeAfQnIZD" crossorigin="anonymous">

ECMAScript module

<script type="module" type="text/javascript">
    import katex from 'https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.mjs';
    ...
</script>
<script nomodule defer src="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.js" integrity="sha384-ZQXoYllNtmeIZKmaU4jDNeTAe8gbbfWsxATRIwJ6zFmlwUpNHuZn8Hsqf8QCa647" crossorigin="anonymous"></script>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.17.0/dist/katex.css" integrity="sha384-xo3oXcu2FwjgZEcZnpFAF2BUCgyAPNcn8CwwPnaN0ajcbe0WxSoeKnFeeAfQnIZD" crossorigin="anonymous">

Use nomodule attribute to provide a fallback for older browsers that do not support ES modules.

Bundler

Use Node.js package managers to install KaTeX and import it in your project. Then bundle using bundlers like webpack or rollup.js. Note that you have to bundle the stylesheet (katex.css) or include it manually.

Download & Host Things Yourself

If you do not want to rely on a CDN, you can serve KaTeX from your own infrastructure. There are two ways to get a release:

Option 1: Pre-built release from GitHub

Each release ships pre-built katex.tar.gz and katex.zip archives. Download one from the KaTeX releases page — look under Assets for katex.tar.gz or katex.zip, not the auto-generated "Source code" download, which only contains the repo source tree without the built files.

After extracting, you will get a katex/ folder containing every file you need:

katex/
├── README.md
├── katex.js              # unminified UMD build
├── katex.min.js          # minified UMD build (recommended for production)
├── katex.mjs             # ES module build
├── katex.css             # stylesheet (font-display: block)
├── katex.min.css         # minified stylesheet
├── katex-swap.css        # stylesheet variant (font-display: swap)
├── katex-swap.min.css
├── contrib/              # optional extensions (each shipped as .js, .min.js, and .mjs)
│   ├── auto-render.js
│   ├── auto-render.min.js
│   ├── auto-render.mjs
│   ├── copy-tex.js
│   ├── copy-tex.min.js
│   ├── copy-tex.mjs
│   ├── mathtex-script-type.js
│   ├── mathtex-script-type.min.js
│   ├── mathtex-script-type.mjs
│   ├── mhchem.js
│   ├── mhchem.min.js
│   ├── mhchem.mjs
│   ├── render-a11y-string.js
│   ├── render-a11y-string.min.js
│   └── render-a11y-string.mjs
└── fonts/                # WOFF2/WOFF/TTF font files (required)

Option 2: npm

npm install katex
# or
yarn add katex
# or
pnpm add katex

After installing, the files you want for hosting live under node_modules/katex/dist/ — same layout as the katex/ folder above.

The npm package also ships the unbuilt TypeScript source (node_modules/katex/src/, node_modules/katex/contrib/, node_modules/katex/katex.ts) for bundler users. Do not link those from your HTML — only the files under dist/ are meant to be served as-is.

Serving the files

Copy the entire folder (or just the pieces you need plus fonts/) into your web server's static directory. The fonts/ directory must stay alongside the CSS file — katex.css references the fonts using relative URLs (e.g. url("fonts/KaTeX_AMS-Regular.woff2")), so moving or renaming fonts/ will break math rendering.

Assuming you copied katex/ to the root of your site, the following HTML will load KaTeX with auto-rendering enabled:

<!DOCTYPE html>
<html>
  <head>
    <link rel="stylesheet" href="/katex/katex.min.css">

    <!-- The loading of KaTeX is deferred to speed up page rendering -->
    <script defer src="/katex/katex.min.js"></script>

    <!-- To automatically render math in text elements, include the auto-render extension: -->
    <script defer src="/katex/contrib/auto-render.min.js"
        onload="renderMathInElement(document.body);"></script>
  </head>
  <body>
    ...
  </body>
</html>

Adjust the /katex/ prefix to match wherever you placed the files. If you only need to render math via the JavaScript API (and not the auto-render extension), you can omit the auto-render.min.js script. Swap katex.min.css, katex.min.js, and contrib/auto-render.min.js for the unminified katex.css, katex.js, and contrib/auto-render.js if you prefer readable files for debugging.

Keeping your copy up to date

Every release publishes the same file names at the same paths, so updating is a drop-in replace. To update:

  1. Get the new release files:
    • Archive: download a fresh katex.tar.gz (or katex.zip) and extract it.
    • npm: run npm install katex@latest (or yarn upgrade katex@latest). The new files appear in node_modules/katex/dist/.
  2. Replace the katex/ directory on your web server with the new files — extracted from the archive, or copied from node_modules/katex/dist/. Keep the same folder name so existing HTML keeps working.
  3. Skim the CHANGELOG for any breaking changes between your old version and the new one.

You can also build from source. See Building from Source for more details.

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