File Info Viewer
Check a file's exact size, type, last modified date and MD5 or SHA checksum. Your files are read locally in your browser and never uploaded.
How to check file information
- Add your files. Drag files onto the box or click to choose them. You can add several at once.
- Pick checksums. MD5 and SHA-256 are on by default. Tick SHA-1 or SHA-512 if you need them.
- Read the details. See the exact size, MIME type, the real file type detected from the file's contents, the last modified date and the hashes.
- Verify a download. Paste the checksum from the publisher's website into the verify box. A matching hash turns green.
What is a file checksum?
A checksum (or hash) is a short fingerprint calculated from every byte of a file. If even one byte changes, the hash changes completely. Software publishers list MD5, SHA-1 or SHA-256 hashes so you can confirm a download is complete and has not been tampered with. SHA-256 is the most common choice today. MD5 and SHA-1 are fine for spotting accidental corruption but are no longer considered secure against deliberate tampering.
Why the "real file type" can differ from the extension
Your browser guesses the MIME type from the file name, so a renamed file can be reported wrongly. This tool also reads the first bytes of the file (its "magic number") to identify common formats such as PNG, JPEG, PDF, ZIP, MP3 and MP4. If the detected type does not match the extension, the file may have been renamed or saved in a different format.
Frequently asked questions
Are my files uploaded to a server?
No. Files are read directly by your browser on your own device. Nothing is uploaded, so it works with private and very large files.
How do I check the size of a file?
Drop the file in the box. The tool shows the exact size in bytes and in KB, MB or GB, using both 1000-based and 1024-based units.
Is there a file size limit?
MD5, SHA-1 and SHA-256 are calculated in small chunks, so even multi-gigabyte files work. SHA-512 uses your browser's built-in crypto engine and is limited to files up to 1 GB.
How do I verify a SHA-256 checksum?
Add the file, then paste the publisher's SHA-256 value into the verify box. The tool compares it with every calculated hash and tells you if it matches.
Why is the last modified date different from when I downloaded the file?
Browsers report the file's last modified time from your file system. Some downloads and archive tools keep the original date set by the publisher.