CRC-64/XZ Checksum Generator

CRC-64/XZ is a 64-bit cyclic redundancy check used to produce a compact checksum from bytes of data. CRCs are designed to detect accidental data corruption in files, archives, protocols, and storage systems. They are useful when you need to compare a payload with an expected checksum, reproduce a value from another tool, or create a quick integrity check for text, but they are not cryptographic hashes and should not be used for passwords, signatures, authentication, tamper resistance, or adversarial collision resistance.

This tool reads the text in the input box as UTF-8 bytes and returns a 16-character uppercase hexadecimal CRC value. The implemented parameter set is CRC-64/XZ: width 64, polynomial 0x42F0E1EBA9EA3693 in normal notation, reflected processing with table polynomial 0xC96C5795D7870F42, initial value 0xFFFFFFFFFFFFFFFF, reflected output, and final xor value 0xFFFFFFFFFFFFFFFF. The standard check string 123456789 produces 995DC9BBDF1939FA.

CRC-64 names are easy to confuse because several variants use 64-bit output and some share the same ECMA polynomial while changing reflection, initialization, or final xor settings. This page calculates CRC-64/XZ, also catalogued as CRC-64/GO-ECMA, not the unreflected CRC-64/ECMA-182 variant whose check value for 123456789 is 6C40DF5F0B497347. When validating data from another system, confirm the exact CRC variant before comparing results.

The generated value depends on the exact input characters after UTF-8 encoding. Whitespace, line endings, letter case, punctuation, and non-ASCII characters all change the output. The calculation runs locally in the browser and does not add file-format framing, length fields, byte swapping, appended check bytes, or any compression container metadata to the text you enter.