Local Hash Calculator

Choose text or a local file, select one SHA algorithm and calculate. The result shows the algorithm, input mode, actual byte count and complete lowercase hexadecimal hash. Copy the hash or select the result manually. Editing the input immediately invalidates the previous result.

Text is encoded as UTF-8, with CRLF and CR line endings normalized to LF. Leading and trailing whitespace is retained; case is unchanged, Unicode is not normalized, escape text is not interpreted, and a BOM is neither added nor removed automatically. An explicit BOM and NUL are included in the calculation. File mode preserves every original byte; the filename, type and modification time are excluded.

The abc example has no newline. Its expected SHA-256 hash is shown below; see RFC 6234 for official vectors for the other algorithms.

Scope and limitations

Text is limited to 200000 UTF-16 code units (some emoji use two) and 800000 encoded bytes; files are limited to 16 MiB. Input is not truncated. The browser must read the entire file, so memory use may exceed its size. Hashing is not encryption, password storage, signature verification or virus detection. It cannot prove a trusted origin or guarantee no collisions; compare against a hash obtained through an independent trusted channel.

This tool does not upload, store or log inputs, files or hashes; the page still loads its resources normally. Clearing only removes page references and does not guarantee secure erasure of browser memory or clipboard history, or protect against malicious extensions or page scripts. A clipboard write that has already started cannot be recalled. Reading can be aborted, but the underlying hash calculation cannot actually be stopped; after cancelling, wait for it to finish before calculating again.

Read progress uses actual byte counts. The hash stage shows only task 0/1. Dashes indicate unknown elapsed time, estimated time remaining or rate. Finishing the file read does not mean the hash is complete.