Checksum calculator
Hash text or files and verify downloads — SHA-256, MD5, SHA-1, SHA-3, BLAKE3, CRC32 and HMAC, free and entirely in your browser. Nothing is uploaded, ever.
the hash appears here — type above or drop a file
That's live SHA-256 — the standard choice. Need its dedicated page with the full write-up? It's at /sha256. Checking a download against a published hash? The verify tool auto-detects the algorithm.
All tools
- sha-256the standard checksum
- verifycheck a file against a hash
- batchSHA256SUMS, in and out
- md5corruption checks only
- sha-1legacy; broken for security
- sha-512bigger margin, 64-bit speed
- sha-384the TLS favourite
- sha-3the Keccak family
- blake3modern and very fast
- crc32error detection, not crypto
- hmackeyed signatures for APIs
- identifywhat hash is this?
Guides & background
Verify a checksum the native way on Windows, macOS or Linux — or start with what a checksum actually is. Choosing an algorithm? MD5 vs SHA-256, SHA-1 vs SHA-256 and SHA-256 vs SHA-512 give the short, honest answers.
Why in your browser?
Because your files are none of our business. Every tool here runs on your machine — WebCrypto and WebAssembly do the math, files are read in small chunks off your disk, and the site makes no network request with your data. There's no server-side hashing, no upload limit, no queue, and it keeps working offline once loaded. The same property makes it fast: a checksum of a multi-gigabyte ISO starts instantly instead of waiting on an upload that shouldn't exist.
Which algorithm should you use?
Verifying someone's download: whatever they published — usually SHA-256. Publishing your own: SHA-256, via a SHA256SUMS file. Hashing gigabytes in your own pipeline: BLAKE3 for speed. Quick corruption check where nobody's attacking: MD5 or CRC32 are fine. Authenticating API calls or webhooks: HMAC-SHA256. When in doubt, SHA-256.
questions
Is anything I type or drop here uploaded?
No. The hashing runs entirely in your browser — there is no server to send anything to. Watch the network tab in your developer tools while hashing: no request carries your data. The tools even keep working offline once the page has loaded.
Can I hash very large files?
Yes. Files are read in 4 MB slices and hashed in a background worker, so memory use stays flat — a 10 GB disk image is fine. A progress bar tracks long runs. More background in what is a checksum.
Why is my hash different from the one a website lists?
Usual suspects: a different algorithm (check the hash length), a corrupted download, or — for text — an invisible difference like a trailing newline. The verify tool detects the algorithm and compares for you.
Do these tools cost anything or need an account?
No. Every tool is free, with no account, no upload limits and no analytics — static files plus your browser doing the math.