CRC16-IBM vs CRC16-MODBUS

CRC16 variants differ by polynomial, initial value, bit reflection (refin/refout), and final XOR. Those small parameter differences produce completely different checksums. In industrial systems, device firmware and serial protocols often mandate one variant explicitly—mix ups will cause verification failures.

If you are debugging a mismatch, check endianness, reflection flags, and whether bytes include headers or addresses. Use our calculators to validate your chosen parameters: CRC16-IBM and CRC16-MODBUS. Keep implementations aligned on both sides and document parameters for future maintenance.

Related tools

Try: CRC16, CRC16-CCITT

FAQ

Are CRC16-IBM and CRC16-MODBUS interchangeable?

No. They use different parameters (polynomial, init, refin/out), yielding different digests for the same data. Use the variant mandated by your protocol.

How do I pick the right CRC variant?

Follow the specification of your device or file format. If you control both ends, choose a well-documented variant and keep parameters consistent.