About this tool
A checksum is a short fingerprint of a file or piece of text, and if even a single byte changes, the fingerprint changes completely. That makes checksums the standard way to confirm a download finished intact, that two files are byte-for-byte identical, or that a file has not been tampered with since it was published. This tool computes five of them at once — CRC32, MD5, SHA-1, SHA-256 and SHA-512 — from text you type or a file you choose, entirely in your browser. Nothing is uploaded anywhere.
CRC32 is fast but only meant to catch accidental corruption (it is what ZIP and Ethernet use); MD5 and SHA-1 are still common in the wild for file integrity checks but are considered cryptographically broken and should not be trusted where security matters; SHA-256 and SHA-512 are the modern, collision-resistant choices most software repositories and package managers publish today. Paste the checksum a vendor or mirror published into the "expected checksum" field and this tool tells you instantly whether it matches — and if so, which algorithm it is.
Frequently asked questions
Which algorithm should I use to verify a download?
Use whichever algorithm the publisher provided the checksum in — that's the only one you can actually compare against. If you have a choice (e.g. the site lists both SHA-256 and MD5), prefer SHA-256: it's the modern standard and, unlike MD5 and CRC32, is also collision-resistant enough to catch deliberate tampering, not just accidental corruption.
Are large files processed in chunks or all at once?
The whole file is read into memory and hashed at once — this keeps the tool simple and works well for typical files, but very large files (multiple gigabytes) may be slow or hit browser memory limits, since there's no streaming/chunked processing.