MIME Type Lookup – Find the MIME Type of Any File Extension Free

Use the free MIME Type Lookup below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.

Why a File’s Extension Is Not Enough

When you download a file or upload one to a website, something has to decide what kind of data it is. A .png file is a picture, a .pdf file is a document, and a .mp3 file is audio, but computers do not guess from the name alone. They use a MIME type: a label with two parts, a category and a subtype, such as image/png, application/pdf, or audio/mpeg. The browser reads the MIME type to decide whether to display a file, play it, or offer it as a download, and a wrong label can make a perfectly good file behave strangely.

This lookup tool answers the question instantly: type an extension or a file name, and get the MIME type from a table built into the page. No request is made, because the table ships with the page itself. That also means the tool works the same way every time, with no server to be slow or unavailable.

How MIME Types Are Structured

A MIME type has a type and a subtype separated by a slash. The common top-level types are text, image, audio, video, application, and font. The subtype says more: text/plain is plain text, text/html is a web page, image/jpeg is a JPEG picture, and application/json is structured data. Some subtypes carry extra structure, such as a vendor prefix: application/vnd.openxmlformats-officedocument.wordprocessingml.document is the long official name for a modern Word document, which is why .docx files have such an unwieldy label.

Two extensions can share a MIME type, and one extension can be ambiguous. Both .jpg and .jpeg mean image/jpeg. The .ts extension can mean a video file or a TypeScript source file, depending on context. A lookup table gives the standard answer, which is the right starting point, but context still matters for the rare ambiguous cases.

Where MIME Types Show Up in Daily Work

Web developers meet MIME types in server configuration. A server that serves a .woff2 font file with the wrong type may make browsers refuse to load it, leaving a site stuck on a fallback font. A server that serves a JavaScript file as text/plain may trigger a browser security block. Fixing these problems usually means adding one line to the server configuration that maps the extension to the right type, and this lookup gives you that line’s key fact.

Upload forms meet MIME types in validation. A form that accepts only images checks the uploaded file’s type against a list such as image/png and image/jpeg. Knowing the exact type matters here, because checking only the file name is easy to fool: renaming a program to photo.png does not make it a picture. Good validation checks the actual file content, but the MIME type list still defines what is allowed.

Email is where MIME was born. Attachments, HTML bodies, and plain-text alternatives are all MIME parts, which is why an email can carry a document, a picture, and a text version of the same message at once. The name Multipurpose Internet Mail Extensions survives from that history, even though the system now serves the whole web.

Common MIME Types Worth Memorizing

For everyday work, a short list covers most cases: text/html for web pages, text/css for stylesheets, text/javascript for scripts, application/json for data, image/png and image/jpeg for pictures, image/svg+xml for vector graphics, audio/mpeg for MP3 audio, video/mp4 for MP4 video, application/pdf for documents, and application/zip for archives. Everything else can be looked up, and that is exactly what this tool is for.

One special value deserves a note: application/octet-stream means generic binary data with no more specific type. Servers use it as a fallback when they do not recognize a file, and browsers respond by downloading it rather than displaying it. If your file downloads instead of opening, a fallback octet-stream label is a likely suspect.

Frequently Asked Questions

What if my extension is not in the table? The table covers the common extensions. Rare or brand-new formats may be missing; check the format’s official documentation for its registered type.

Can I look up a type in reverse? Yes. Typing a full MIME type such as audio/mpeg returns the extensions that use it.

Does the extension guarantee the file’s real type? No. An extension is only a name. The real type comes from the file’s content, which is why upload validation should never trust the name alone.

Type the extension, get the label, and configure your server or form with the right value the first time.

Related Tools

Also available in Spanish: Buscar Tipo MIME Gratis – Qué MIME Tiene cada Extensión.

More free tools: cURL Command Builder – Build cURL Commands Free Online, API Request Code Generator – Generate Fetch and Python Snippets Free, Open Graph Card Preview – Preview Social Share Cards Free Online, URL Query Parameter Editor – Edit URL Query Parameters Free Online, JSON Key Sorter – Sort JSON Keys Alphabetically Free Online, SSH Config Generator – Generate SSH Config Files Free Online, Nginx Config Generator – Generate Nginx Server Blocks Free Online, Env File Generator – Generate .env Files Free Online, Remove Duplicate Lines Online Free – Delete Repeated Lines Fast.