SHA-256 checksum of text or a file
Compute SHA-256, SHA-512 or SHA-1 in the browser via Web Crypto. Hex and Base64 output. File is not uploaded.
SHA-256 is the checksum you want for downloads and artifacts. Match the published hex; a single-bit change flips the digest. SHA-512 is the same family with a longer digest.
SHA-1 stays only to check old published sums. Do not use it for new integrity. MD5 is not offered: it is not in Web Crypto and it is broken for collision resistance.
The file is read locally. Large files may take a few seconds. For passwords use the generator; hashing a password with SHA-256 without a salt is not a login scheme.
SHA-256 of the empty string is e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855. The same letters with a trailing newline are a different digest. The hash does not store the text: you cannot invert it, you can only recompute and compare. SHA-1 still appears in old signatures and is not the default here. A file hash covers the bytes, so renaming the file does not change it and editing one byte does. This page opens on SHA-256.
FAQ
Why no MD5?
Not in Web Crypto, and collisions are cheap. Use SHA-256.
Hex or Base64?
Hex is what most checksum pages publish. Base64 is shorter for embedding.
Is the file uploaded?
No. The browser hashes it in place.