MIME Type Lookup: Find Content-Type by Extension
Look up MIME/Content-Type for any file extension or filename. Instant lookup, no server required.
Try the free online tool mentioned in this guide:MIME Type Lookup
What is a MIME type?
MIME (Multipurpose Internet Mail Extensions) types describe data format. Servers use them to tell browsers how to handle files:
Content-Type: image/jpeg → browser displays as image
Content-Type: application/pdf → browser offers download
Content-Type: text/plain → browser renders as text
File extension alone doesn't tell the browser how to handle it; MIME type does.
Common MIME types
Text files:
- .txt → text/plain
- .html → text/html
- .css → text/css
Images:
- .jpg → image/jpeg
- .png → image/png
- .gif → image/gif
Application files:
- .pdf → application/pdf
- .zip → application/zip
- .json → application/json
Why MIME types matter
- HTTP headers —
Content-Typetells clients how to interpret response. - File uploads — validate uploaded file types.
- Email attachments — specify file formats.
- APIs — tell client what format data is in.
Lookup workflow
1. Type filename or extension — e.g., document.pdf or .xlsx.
2. Click lookup or instant search.
3. Copy MIME type — grab application/vnd.ms-excel.
4. Use in code — set HTTP header or validation.
Frequently asked questions
Can one extension have multiple MIME types?
Rarely. `.js` is almost always `application/javascript`. Server configuration can override defaults.
What if the MIME type is wrong?
Browsers may misinterpret files. Verify in your web server config (`.htaccess`, nginx, etc.).
Are there unofficial MIME types?
Yes, apps use custom types like `application/vnd.custom`. Lookup tools show official types.