Hash / Checksum

Calculates eleven digests for UTF-8 text or the unchanged bytes of a file, entirely locally in the browser. Spaces, line breaks and empty input count exactly. Text is encoded without an added byte-order mark; files are neither interpreted as text nor uploaded. Use Calculate or Ctrl/Meta+Enter; choosing a file starts calculation directly.

SHA-256, SHA-384 and SHA-512 come first. SHA-1 and MD5 are legacy compatibility algorithms unsuitable for security checks. CRC-32 (IEEE), Adler-32, FNV-1a 32/64 and BSD/SysV sum are non-cryptographic checksums. A digest is not encryption and does not prove authenticity by itself: compare it with a trusted reference. Values use lowercase hexadecimal digits; Copy copies the complete value without its label. Long values remain fully visible.

The limit is 64 MiB per text or file; the entire input is held in memory. Calculation runs in a dedicated worker to keep the interface responsive. Progress counts completed algorithms out of eleven, not bytes read or evenly distributed time. Cancel, editing, a new calculation or leaving the tool discards the previous job. Retry after an error; browsers without workers or Web Crypto cannot calculate this tool.

Text (including empty input) and completed checksum snapshots stay in this browser’s local storage. File bytes are not saved; the file name, size and checksum snapshot can be restored without rereading it. Select the file again to calculate it afresh. Editing text clears old results. Text above the automatic storage budget stays available during navigation in this app; a warning asks you to save it before reloading, which recovers the previous saved copy. Text backup saves and loads UTF-8 text without trimming spaces, line breaks or a leading byte-order mark; loading does not calculate automatically. Malformed UTF-8 is rejected without replacing your text. The editor allows up to 64 Mi UTF-16 code units; a text backup can contain up to 192 MiB of UTF-8, subject to that editor limit. Hash calculation still accepts at most 64 MiB of encoded bytes. The editor normalizes CR and CRLF line endings to LF; hashing a file uses its original bytes.