CRC-16 Checksum

The CRC-16 Checksum calculator computes CRC-16 (Cyclic Redundancy Check with a 16-bit polynomial) values across multiple standard polynomial variants: CRC-16-CCITT (0x1021), CRC-16-IBM/ARC (0x8005), CRC-16-MAXIM, CRC-16-USB, and others. CRC-16 is the dominant error detection algorithm in industrial serial communication protocols — Modbus RTU mandates CRC-16-IBM for every frame, XMODEM and YMODEM file transfer protocols use CRC-16-CCITT, and many Bluetooth LE protocols use CRC-16 variants for packet validation.

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How to Use

Enter or paste data into the input field and select the CRC-16 polynomial variant matching your target protocol (CRC-16-IBM for Modbus, CRC-16-CCITT for XMODEM/YMODEM, etc.). The checksum is computed instantly and displayed in hexadecimal (big-endian and little-endian byte order). Compare the output against the expected checksum from your device or specification document to verify correctness.

Common Use Cases

• •Computing CRC-16-IBM (polynomial 0x8005) checksums to validate Modbus RTU protocol frames in industrial automation and SCADA systems
• •Generating CRC-16-CCITT checksums for XMODEM or YMODEM file transfer protocol implementations over serial or modem connections
• •Verifying data integrity in embedded IoT device firmware by computing and checking CRC-16 values of sensor data packets
• •Debugging serial communication frames by comparing computed CRC-16 values against the checksum bytes appended by the device
• •Implementing and validating CRC-16 error detection in custom binary communication protocol libraries for microcontroller projects

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