File checksum calculator
Hash files of any size and verify downloads, without uploading them.
How it works
- 01Drop one or more files of any size.
- 02Pick the algorithms you need. They run in parallel, in background workers.
- 03Paste the checksum from the download page to see whether the file matches.
Questions
›How do I verify a download?
Drop the file, then paste the checksum the publisher lists (often labelled SHA256 or "checksum"). The algorithm is recognized from its length, so you don't need to pick it. A match means your copy is byte-for-byte identical to theirs.
›Can it handle very large files?
Yes. Files are read in 8 MB pieces and hashed incrementally in background workers, so even a disk image many gigabytes in size never has to fit in memory and the page stays responsive. Speed depends on your device and disk.
›Which algorithm should I use?
SHA-256 is the standard today. MD5 and SHA-1 are still fine for spotting accidental corruption, but they are broken against deliberate tampering, so don't rely on them for security. CRC32 is a quick check used inside zip files.
›Can I paste sha256sum output?
Yes. A bare hash, a line like "hash filename" from sha256sum, BSD style "SHA256 (file) = hash" and SRI strings like "sha384-…" all work, in upper or lower case.
›Are my files uploaded anywhere?
No. Your files are processed on your own device by your browser. They never touch our servers, so there are no upload waits, no size caps from us, and nothing to delete afterwards.