Guide updated:
Check a file signature instead of relying only on the extension in its name.
Open this guide using the “How to use this tool” link below the tool name. It includes steps, screenshots and videos for computers and phones.
Before you start
Choose a local file. Detection helps identify likely formats; it does not repair a file or prove that it is safe.
Try with a demonstration file — document.pdf
These small files were created for this guide and contain no personal data.
Step-by-step instructions
- Open File Type Detector and choose the file to inspect.
- Use Detect type and wait for the report. The file is inspected for recognizable content signatures.
- Review the likely format, MIME type and signature details shown in the result.
- Compare the detected format with the file name extension. An extension mismatch needs checking before renaming anything.
- Copy or export the available report and use an application that supports the identified format.
On a computer
Use the full-width working panel to compare the source, settings and result. Keep the original file so you can try another setting without replacing it.
On a phone
Choose the source from Files or your device file manager. Scroll down to the settings and result; keep this tab open until the operation finishes.
In Safari on iPhone, open the sharing menu and choose Save to Files if the result opens in a new tab. In Android Chrome, check Downloads. Keep this tab open until processing finishes.
For a better result
Keep the original name until you have a verified copy. Renaming an extension does not convert the file contents.
Screenshots and video
Desktop demonstration
The recording shows the English interface. Follow the translated steps above; the controls are in the same order. This recording shows a demonstration input and the resulting output in the tool.
Phone demonstration
The recording shows the English interface. Follow the translated steps above; the controls are in the same order. This recording shows a demonstration input and the resulting output in the tool.
Questions and troubleshooting
Why is the type unknown?
Some formats have no distinctive signature, and damaged or very short files may not contain enough readable bytes.
Can a detected file still be harmful?
Yes. A recognizable format is not a security scan. Use your usual checks before opening untrusted content.
If you see a message that the service is overloaded, wait and try again later. A failed attempt does not mean that your source file has changed.
