MIME Type Lookup

What this tool does

MIME Type Lookup looks up the standard MIME (media) type for a file extension like .json or .pdf, or finds the matching extension(s) for a MIME type like image/jpeg, from a built-in table of around 70 commonly used web, document, media and archive formats.

Setting a Content-Type header, configuring a file upload filter, or just double-checking what MIME type a browser expects for a given file extension, all require looking up the exact, correctly cased MIME string, which isn’t always obvious or memorable (is a .jpg file image/jpeg or image/jpg? It’s the former).

This lookup covers around 70 commonly used file extensions, spanning web formats, documents, images, audio, video, fonts and archives, and works in both directions: enter an extension to get its MIME type, or enter a MIME type to find which extension(s) commonly use it.

How to use MIME Type Lookup

1. Choose a Direction: extension to MIME type, or MIME type to extension.
2. Enter the Extension or MIME type you want to look up (with or without a leading dot on the extension).
3. Read the matching result.
4. Check the notes for any relevant caveats about multiple matches.

Tips for better results

• Entering an extension with or without its leading dot (json or .json) both work the same way.
• Some MIME types map to more than one extension, like image/jpeg covering both .jpg and .jpeg; the reverse lookup shows every known match from the table.
• This table focuses on the single most standard, widely supported MIME string for each extension; a small number of legacy or vendor-specific MIME strings exist for some formats but aren’t included here to keep results unambiguous.
• For an extension genuinely not in this roughly 70-entry table, the generic application/octet-stream MIME type is the conventional fallback used by many systems for unknown binary files.

Common use cases

• Setting the correct Content-Type header for a file being served or uploaded.
• Checking which file extensions a given MIME type filter (such as an HTML file input’s accept attribute) would match.
• Quickly confirming the standard MIME type for a file format while writing server or API code.
• Double-checking a MIME type found in a log, header or configuration file against a known extension.

Common mistakes to avoid

• Assuming every file extension has exactly one MIME type and vice versa; several common ones, like .jpg/.jpeg, intentionally map to the same MIME type, which this tool’s reverse lookup shows explicitly.
• Using a MIME type not found in this roughly 70-entry table for a highly specialised or vendor-specific format and assuming it simply doesn’t exist; it likely does, just outside this tool’s intentionally focused, common-format scope.
• Forgetting that setting an incorrect Content-Type header can cause a browser or client to misinterpret or refuse a file, even if the file’s actual content is perfectly valid.