MIME Type Lookup
Find the correct Content-Type for a file extension, or the extensions for a MIME type — instantly, from a built-in lookup table in your browser.
Updated
How to use MIME Type Lookup
The MIME Type Lookup tool maps file extensions to their official MIME types and back, instantly in your browser. Type an extension like png or pdf to get the correct Content-Type header value, or enter a MIME type such as image/jpeg to see every extension that uses it. The built-in table covers the common web, document, media, font and archive formats you meet when configuring servers, building file uploads, or setting download headers — all without a network request.
- Choose "Extension → MIME" or "MIME → Extensions".
- Type the file extension (with or without a leading dot) or the MIME type.
- The matching MIME type or list of extensions appears immediately.
- Copy the result to use in your HTTP headers or configuration.
- Switch modes at any time to look up the other direction.
Your data never leaves your device — 100% private processing.
What a MIME type is and where it is used
A MIME type — formally a media type — is a two-part label like type/subtype that identifies the format of a piece of data, for example text/html or image/png. It originated in email (the name stands for Multipurpose Internet Mail Extensions) but is now used everywhere on the web. The most important place you meet it is the HTTP Content-Type response header, which tells a browser whether to render content, display it inline, or download it. MIME types also appear in HTML form enctype attributes, the accept attribute of file inputs, data URIs, and the manifest files of progressive web apps. Sending the wrong type is a common cause of files downloading instead of displaying, or scripts being blocked.
| Extension | MIME type | Category |
|---|---|---|
| .html | text/html | Markup |
| .json | application/json | Data |
| .png | image/png | Image |
| .mp4 | video/mp4 | Video |
| .woff2 | font/woff2 | Font |
| .zip | application/zip | Archive |
Why correct MIME types matter for security and behaviour
Beyond simply making files display correctly, accurate MIME types are a security feature. Modern browsers apply a protection called MIME-type sniffing prevention: when you send the header X-Content-Type-Options: nosniff, the browser trusts your declared Content-Type instead of guessing from the bytes. If you mislabel a user-uploaded file — say serving an HTML file as image/png — sniffing protection can stop a script from executing, mitigating certain cross-site scripting attacks. Conversely, serving JavaScript with the wrong type can cause strict environments to refuse to run it. Getting the MIME type right therefore affects not just whether a file works, but whether your site stays safe, which is why a quick, reliable lookup is a handy part of any developer toolkit.
Worked examples
Extension to MIME
Inputs: webp
Result: image/webp
MIME to extensions
Inputs: image/jpeg
Result: .jpg, .jpeg
Glossary
- MIME type
- A two-part media type label such as image/png that identifies the format of a file or stream of data.
- Content-Type
- The HTTP header that carries a resource’s MIME type so the client knows how to handle it.
- Subtype
- The second half of a MIME type (the part after the slash) that names the specific format within a category.
- application/octet-stream
- The generic MIME type for arbitrary binary data, used when no more specific type is known.
- MIME sniffing
- A browser behaviour that guesses a file’s type from its content, which can be disabled with the nosniff header.
Related reading
Frequently Asked Questions
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Why use MIME Type Lookup?
- Find the correct Content-Type for any common file extension
- Reverse-lookup every extension that maps to a given MIME type
- Covers images, audio, video, documents, fonts and archives
- No network request — the lookup table is bundled and runs locally
- Copy the result with one click for use in code or server config
Common use cases
- Set the right Content-Type header when serving a file from a server
- Validate the MIME type of an uploaded file against its extension
- Configure a web server or CDN to serve a new file format correctly
- Look up the extension to use when saving a file received with a MIME type
- Debug why a browser downloads a file instead of displaying it inline
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