File Checksum
Updated May 7, 2026Verify a downloaded file hash against the expected value to confirm integrity.
Expected Hash (optional)
Drop a file to verify its checksum
Max: 500 MB
When to Verify Checksums
- • Downloads - Verify ISO files, software installers, firmware updates
- • File transfers - Ensure files weren't corrupted during copy
- • Security - Verify files haven't been tampered with
- • Backups - Confirm backup integrity
Features
- 100% Client-side file processing (Upload-free and secure)
- Supports huge files (Gigabytes in size) via chunked reading
- Generates MD5, SHA-1, SHA-256, and SHA-512 checksums
- Progress bar visualization for large file processing
- Auto-compare input to instantly verify against an expected hash
- Drag and drop interface support
Common Use Cases
- Verifying Linux OS ISO downloads to ensure they haven't been tampered with
- Checking large game patches or mod archives for integrity
- Validating database backup restorations before deploying them
- Ensuring secure transfer of sensitive documents or forensic evidence
Understanding File Checksums
A checksum is a cryptographic hash generated from the raw bytes of a file. When downloading large files or sensitive software from the internet, data can be altered by network errors, broken connections, or malicious man-in-the-middle attacks.
Software publishers often provide a checksum (usually a SHA-256 hash) next to the download link. By using this tool to compute the hash of your locally downloaded file and comparing it to the publisher's hash, you prove that every single bit of your local file is identical to the original.
Browser Security: Modern browsers support the Web Crypto API, allowing this tool to read your file directly from your hard drive into memory, calculate the hash, and discard the memory. The file never travels over the network, guaranteeing total privacy and enabling the processing of files much larger than your internet upload speed could handle.
Examples
1. Download Ubuntu Linux ISO (3GB)
2. Copy the SHA256 string from the Ubuntu website
3. Drag the ISO file into this tool
4. Paste the expected hash into the "Compare" box
5. Tool confirms the file is authentic and uncorrupted.Frequently Asked Questions
No. Your file is read locally by your web browser using HTML5 File APIs. It never leaves your device. You can verify this by disconnecting from the internet and the tool will still work perfectly.
Hashing requires mathematical operations to be performed on every single byte of the file. A 5GB file contains 5 billion bytes. While algorithms are fast, the speed is largely bottlenecked by how fast your computer's hard drive (SSD/HDD) can read the data into memory.
It means the file you downloaded is not identical to the file the publisher released. This could be due to an incomplete download, network corruption, or worst-case, the file was intercepted and replaced with malware. You should delete the file and download it again.
💡 Tips
- If you download software from a third-party mirror site, always verify the checksum against the hash published on the <em>official developer's website</em> to ensure the mirror hasn't inserted malware.
- For forensic analysis, generating a SHA-256 hash of a hard drive image establishes a chain of custody, proving the evidence was not altered after acquisition.