CRC-16 Calculator
Calculate Modbus RTU CRC-16 checksums for your data frames
Calculate CRC
Enter your Modbus data as hexadecimal values (without CRC). Spaces and common separators are automatically removed.
Example Data
Click on any example to load it into the calculator
Read Holding Registers (Addr: 1, FC: 03, Start: 0, Count: 10)
01 03 00 00 00 0AWrite Single Register (Addr: 1, FC: 06, Reg: 100, Value: 1234)
01 06 00 64 04 D2Read Coils (Addr: 17, FC: 01, Start: 19, Count: 19)
11 01 00 13 00 13About Modbus CRC-16
Modbus RTU uses CRC-16-ANSI (also known as CRC-16-IBM) for error detection. The polynomial used is 0xA001 (reverse of 0x8005).
The CRC is calculated over all bytes in the message except the CRC itself. The result is transmitted with the low byte first, followed by the high byte.
When receiving a Modbus RTU frame, the receiver calculates the CRC of the received data (excluding the CRC bytes) and compares it with the transmitted CRC to verify data integrity.