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ToolSuite
File & Archive Tools

File Extension Detector

Find the correct extension for a file with the wrong name or no name at all.

or drag it here

Any file · up to 200 MB

Processed in your browser

Fill in the form and press “Detect extension” to see the result here.

How to use it

  1. 1Select your file, or drag and drop it onto the upload area.
  2. 2Adjust the options if you need something other than the defaults.
  3. 3Press the button. Everything happens on your device.
  4. 4Download the result.

About the File Extension Detector

Useful for files recovered from a cache, a temporary folder or a data recovery tool, where the name has been lost but the contents are intact.

Questions people ask

Is your file uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your file never leaves your device. You can confirm it by opening your browser's network panel while the tool runs, or by disconnecting from the internet after the page has loaded.

Is it free, and do I need an account?

Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.