File Format Detector - Identify Any File Format Instantly
Detect any file format instantly with our free online format detector. Supports 1000+ file types including images, documents, audio, video, and archives.
100% Private & Secure
All file analysis happens in your browser. Your files never leave your device or get uploaded to any server.
Click to upload any file or drag & drop
Supports all file types: images, documents, audio, video, archives, executables
Maximum file size: 100MB per file
Supported Format Categories
Unknown Format
Hex View & Magic Numbers
Hex view will appear here after file upload
Format Database
Similar Formats
Similar formats will appear here
Actions
Analyzing File Format
Reading file headers and comparing with 1000+ known formats...
Common File Format Examples
Complete Guide to File Format Detection
File format detection is the process of identifying the type of a file by examining its contents, particularly the file signature or "magic numbers" at the beginning of the file. Unlike file extensions which can be easily changed, magic numbers provide reliable identification of file formats.
Why File Format Detection Matters
- Security: Detect malicious files masquerading as safe types
- Data Recovery: Identify corrupted files with missing extensions
- Compatibility: Ensure files are opened with correct applications
- Forensics: Analyze files in digital investigations
How File Format Detection Works
Read File Headers
The tool reads the first 1-8 bytes of the file (the "magic numbers") which uniquely identify the format.
Compare with Database
The magic numbers are compared against a database of 1000+ known file format signatures.
Analyze File Structure
For ambiguous cases, additional file structure analysis is performed to confirm the format.
Provide Detailed Report
A comprehensive report including format, MIME type, category, and technical details is generated.
Common File Magic Numbers
| File Format | Extension | Magic Numbers (Hex) | ASCII Representation |
|---|---|---|---|
| JPEG Image | .jpg, .jpeg | FF D8 FF | ÿØÿ |
| PNG Image | .png | 89 50 4E 47 | ‰PNG |
| PDF Document | 25 50 44 46 | ||
| ZIP Archive | .zip | 50 4B 03 04 | PK |
| MP3 Audio | .mp3 | 49 44 33 | ID3 |
| Windows Executable | .exe | 4D 5A | MZ |
Magic Number Detection
Analyzes the first few bytes of a file which contain unique identifiers for different formats. This is the most reliable method as these bytes cannot be easily faked.
File Extension Analysis
Examines the file extension (.jpg, .pdf, etc.). Least reliable as extensions can be easily changed or removed, but useful as secondary verification.
Structure Analysis
Examines internal file structure, headers, and footers. Used for complex formats and when magic numbers are ambiguous or missing.
Statistical Analysis
Uses statistical methods to analyze file content patterns. Helpful for identifying encrypted, compressed, or proprietary formats.
Practical Use Cases for Format Detection
Security Scanning
Detect malicious files disguised with false extensions. For example, an executable (.exe) renamed to look like a document (.pdf).
Data Recovery
Recover files with corrupted or missing extensions by identifying their true format through magic number analysis.
Digital Forensics
Analyze files in digital investigations to identify hidden or obfuscated data based on their true format.
Software Development
Implement proper file handling in applications by accurately detecting uploaded file formats regardless of extension.
FAQ - File Format Detector
Q: What is a magic number in file format detection?
A: A magic number is a constant numerical or text value used to identify a file format. These are typically the first few bytes of a file and are unique to each format. For example, all JPEG images start with "FF D8 FF" in hexadecimal, and all PDF files start with "%PDF" (25 50 44 46 in hex). Magic numbers are more reliable than file extensions because they can't be easily changed without corrupting the file.
Q: How accurate is your format detector?
A: Our format detector has a database of 1000+ file formats with their magic numbers and file structures. For common formats like JPEG, PNG, PDF, ZIP, etc., accuracy is nearly 100%. For rare or proprietary formats, accuracy depends on whether the format is in our database. We continuously update our database with new formats. The tool also provides confidence levels (High/Medium/Low) to indicate detection certainty.
Q: Is it safe to upload my files to this tool?
A: Absolutely safe! All file analysis happens locally in your web browser using JavaScript. Your files are never uploaded to any server, stored anywhere, or accessible by anyone else. This is a 100% client-side tool that works entirely on your device. You can verify this by disconnecting your internet after loading the page - the tool will still work.
Q: What's the maximum file size I can analyze?
A: You can analyze files up to 100MB. For format detection, we only need to read the first few kilobytes of a file (where magic numbers are located), so even large files are processed quickly. If you have files larger than 100MB, consider using desktop software for analysis, or check if the file format can be identified by just examining the beginning of the file.
Q: Can this tool detect corrupted or modified file formats?
A: Yes, to some extent. The tool can detect files with incorrect extensions, and it can often identify the true format even if the extension is wrong or missing. For partially corrupted files, if the magic numbers are intact, detection is usually successful. For severely corrupted files where the header is damaged, detection may fail or provide low-confidence results. The hex viewer can help manually inspect such files.
How to Use the Format Detector:
- Click the upload area or drag and drop any file into the designated area
- The tool will automatically analyze the file's magic numbers and structure
- View the detected format, MIME type, category, and technical details
- Examine the hex view to see the file's magic numbers and raw data
- Check similar formats if the detection confidence is not 100%
- Use the information to determine the correct application to open the file
- Click "Detect Another File" to analyze more files
Important Notes:
- This tool works entirely in your browser. Your files are never sent to any server.
- The tool has a database of 1000+ file formats with their magic numbers and signatures.
- File extensions can be misleading or wrong. Always trust magic number detection over file extensions.
- The hex viewer shows raw file data. Magic numbers are highlighted in green for easy identification.
Why Choose Web tool Bazar Format Detector?
Complete Privacy
All file analysis happens in your browser. Your files never leave your device or get transmitted over the internet.
Extensive Database
Database of 1000+ file formats with magic numbers, signatures, and technical specifications.
Hex Viewer
Built-in hex viewer to examine file magic numbers and raw data for advanced analysis.
About Web tool Bazar's File Analysis Tools
Developed by digital forensics and file format experts, Web tool Bazar's Format Detector is trusted by IT professionals, digital archivists, security analysts, and developers worldwide to accurately identify file formats and ensure data integrity.
Our tools are built with professional-grade file analysis algorithms and are continuously updated with new file formats and detection methods. We're committed to providing free, privacy-focused tools for all your file analysis needs.