The file checksum calculator computes MD5, SHA-1, SHA-256, SHA-384, or SHA-512 hashes from any file you drop on it — used to verify that a downloaded ISO or installer matches the hash the publisher posted. All computation happens locally in the browser; the file never leaves your machine.
Which algorithm to pick
| Algorithm | Output length | Notes |
|---|---|---|
| MD5 | 32 hex chars | Fast; fine for casual integrity checks. Cryptographically broken since 2004 — do not use for security. |
| SHA-1 | 40 hex chars | Used in older Git commits and legacy systems. Practical collision attack demonstrated in 2017. |
| SHA-256 | 64 hex chars | The current default for most download verification pages. First choice for new use. |
| SHA-384 | 96 hex chars | Higher security margin; used in TLS certificate signing. |
| SHA-512 | 128 hex chars | Maximum strength; suited for archiving large file collections where integrity must hold for years. |
Most modern Linux distributions (Ubuntu, Debian, Fedora) now publish SHA-256 checksums. When the download page shows a .sha256 file alongside the ISO, SHA-256 is the right pick.
Verifying a download step by step
- Find the official checksum string on the release page (often inside a
.sha256or.md5file — one line, one hash) - Drop your downloaded file into the upload area
- Select the matching algorithm
- Compare the tool's output character-by-character against the official string
Hashes are case-insensitive: a3f2… and A3F2… are identical. If every character matches, the file is intact. One differing character means the file is different — download again.
Large files and browser limits
The browser holds the entire file in memory during processing. Files above roughly 10 GB may cause the tab to crash on machines with limited RAM. For very large files, use the command line instead:
# macOS / Linux
shasum -a 256 filename.iso
md5sum filename.iso
# Windows PowerShell
Get-FileHash filename.iso -Algorithm SHA256