Calculate text checksums
Calculate non-cryptographic checksums from pasted text. Choose a family, select an algorithm, and copy the hexadecimal result from the output pane.
Checksums are built for error detection, not security. CRC variants are common in file formats, storage systems, embedded protocols, and network records because small byte changes produce different check values. They do not replace SHA-256, BLAKE3, or password hashing algorithms.
Batch rows
Batch by newline treats each line as a separate value. Paste a list of filenames, identifiers, payload snippets, or protocol fields, then compare the returned list with another system.
Trim lines removes leading and trailing whitespace before each checksum is calculated. Leave it off when spaces are part of the value being checked.
Text bytes and Unicode
The calculator encodes text as UTF-8 before running the selected algorithm. That means é, emoji, and other non-ASCII characters are processed as their UTF-8 byte sequences.
Unicode normalization converts visually similar forms into a consistent representation before encoding. It is helpful when text may come from different editors, spreadsheets, or copied web pages.
Choosing an algorithm
Use CRC-32 when matching ZIP, PNG, gzip, or many common checksum listings. Use CRC-32C when a system names Castagnoli specifically. Use a named CRC-16 profile when the receiving device or protocol expects that exact profile; the polynomial, initial value, reflection rules, and final XOR all matter.
Adler-32 and Fletcher checksums are compact and older. BSD and System V checksums mainly appear in Unix compatibility cases.