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Custom CRC Calculator

Compute a CRC with your own polynomial, initial value, reflection and final XOR — the parameters that make two CRC tools disagree.

Input

CRC-32

CBF43926

The check value for the string "123456789" is the standard way to identify a CRC variant — CRC-32 gives CBF43926, CRC-16/ARC gives BB3D.

A checksum, not a hash

CRC is built to catch accidents — a flipped bit on a wire, a truncated file — not attacks. It is fast enough to run on every packet, and it detects all single-bit errors and all burst errors shorter than its width.

It is trivially forgeable, though: anyone can craft different data with the same CRC. If an adversary is in the picture, you need SHA-256, not a checksum.

Frequently asked questions

Which CRC variant is this?

CRC-32 here is the IEEE 802.3 polynomial used by ZIP, gzip and PNG. CRC-16 is the ARC variant used by Modbus and many serial protocols.

Why is my CRC different from another tool?

CRC is a family, not one algorithm. Implementations differ in polynomial, initial value, bit reflection and final XOR — all of which change the result for the same input.

Related tools

CRC-32 ChecksumCompute the CRC-32 checksum used by ZIP, PNG and gzip. Detects accidental corruption — it is not a security hash.CRC-16 ChecksumCompute a CRC-16/ARC checksum, the variant used by Modbus and many serial protocols.MD5 Hash GeneratorGenerate an MD5 checksum of text or a file. Fast and universal, but broken for security — use SHA-256 for anything that matters.SHA-1 Hash GeneratorCompute a SHA-1 digest of text or a file. Still used by Git and legacy systems, but no longer collision-resistant.SHA-256 Hash GeneratorCompute a SHA-256 digest of text or a file — the default choice for checksums, signatures and content addressing.SHA-384 Hash GeneratorCompute a SHA-384 digest — SHA-512 truncated, used where a 384-bit output is specified.