Checksum Calculator

Digest the exact UTF-8 text

Paste text, choose a SHA algorithm, and select Calculate checksum. Web Crypto encodes the exact characters as UTF-8 and returns a lowercase hexadecimal digest.

What a checksum can show

Run the same bytes through the same algorithm and the digest should match. Comparing against an expected digest obtained through a trusted channel can detect accidental corruption or an unexpected change. Even a tiny text change normally produces a very different digest.

Text encoding matters

This page hashes UTF-8 bytes made from the text box. Capitalization, spaces, line endings, and invisible trailing characters affect the result. A checksum published for a downloadable file will not necessarily match text pasted from that file because copying can alter bytes or omit non-text content.

Worked example

SHA-256 of the three ASCII characters abc is ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad. Adding a line break creates a different input and therefore a different checksum. Empty text is also valid and has its own standard digest.

Algorithm choices

SHA-256, SHA-384, and SHA-512 are modern SHA-2 digests. SHA-1 remains here only for compatibility checks against older published values; collision weaknesses make it unsuitable for new adversarial integrity designs. Both sides of a comparison must use the identical algorithm.

Security scope and limitations

A checksum is not encryption: input is not hidden and cannot be recovered from the digest. An unkeyed digest is not authentication, a digital signature, or proof of who supplied data. An attacker who can replace both content and expected checksum can defeat a simple comparison. This is also not password hashing; passwords require a dedicated slow, salted password-hashing system.