Modbus Register Decoder & CRC Checker
Paste a Modbus RTU or TCP frame in hex. Check the CRC and decode registers.
How it works
Modbus RTU frames end in a CRC-16 sent low byte first; TCP frames use a 6-byte header and no CRC. The tool detects the format, checks the CRC, decodes the function code and byte counts, and flags exceptions.
Float and 32-bit values depend on your device’s word order, so every pair of registers is shown as ABCD, CDAB, BADC and DCBA. Pick the one that gives sensible numbers. Example: registers 0x41C8 0x0000 read as float32 ABCD give 25.
This tool only decodes data you paste; it never connects to a device. Runs entirely in your browser; nothing is uploaded. As-is local-first edge utility, provided without warranty.