ByteScope

File Hash Calculator

Hash files with every common algorithm at once and verify checksums — locally.

Your files never leave your browser — all processing is local.

Drop files here

any file, any size, multiple files — also accepts .sha256/.md5/.sha1 checksum files to verify a batch

About this tool

Drop any file and this calculator computes MD5, SHA-1, SHA-256, SHA-512, SHA-3, CRC32, xxHash64 and BLAKE3 in a single pass — the file is read once and fed to every hasher simultaneously in a Web Worker, so even multi-gigabyte disk images finish quickly with a live progress bar. Files are processed in 64 MB chunks via streaming, so memory stays flat no matter the size, and nothing is ever uploaded.

The most common reason to hash a file is to verify a download. Paste the checksum from the vendor's site and the tool auto-detects which algorithm it is from its length, compares it against the computed value, and gives you an unmissable match / mismatch verdict. You can also drop a .sha256 or .md5 checksum file to verify a whole batch of files at once.

A text mode hashes typed or pasted strings with the same algorithms, with an optional HMAC key for keyed hashes. Everything runs locally via WebAssembly (hash-wasm) — your files and secrets never leave your device, which also makes this safe for files you could never send to an online service.

Frequently asked questions

Is my file uploaded to compute the hash?
No. The file is read locally in your browser and hashed in a Web Worker using WebAssembly. There is no upload request — you can verify in your browser's DevTools Network tab — which also means there is no practical file-size limit imposed by a server.
How do I verify a downloaded file against its checksum?
Drop the downloaded file, then paste the checksum string published on the vendor's website into the compare box. The tool detects the algorithm from the string's length (32 hex chars = MD5, 64 = SHA-256, …), computes that hash, and shows a clear match or mismatch verdict.
Which algorithm should I use?
For integrity verification, use whatever the publisher provides — most commonly SHA-256. For your own use, SHA-256 is the safe default; BLAKE3 and xxHash64 are much faster when you only need integrity checking, not security. MD5 and SHA-1 are cryptographically broken and should only be used to match legacy published checksums.
Can it handle very large files?
Yes. The file is streamed in 64 MB chunks with Blob.slice, so a 20 GB disk image hashes without loading into memory. All selected algorithms are computed in the same single read pass, and a progress bar tracks the work.
Does it support HMAC?
Yes — in text mode you can supply a key to compute HMAC values (e.g. HMAC-SHA-256) for API-signature debugging, alongside plain hashes of the input string.