CRC Calculator

Calculate CRC checksums for hex or ASCII data using standard algorithms. Includes CRC-8, CRC-16, and CRC-32 presets commonly used in IoT and embedded protocols.

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Width32 bits
Polynomial0x04C11DB7
Init0xFFFFFFFF
Reflect InYes
Reflect OutYes
XOR Out0xFFFFFFFF

How to Use

Select the input format (hex bytes or ASCII text) and the CRC algorithm, then enter your data. The checksum updates live as you type.

  • Hex mode: enter raw bytes like DEADBEEF, 0xFF, or space-separated 31 32 33
  • ASCII mode: enter plain text like 123456789 (the canonical test string)
  • The algorithm parameters panel shows the polynomial, init value, reflection, and XOR-out for the selected preset

What is CRC?

A cyclic redundancy check (CRC) is an error-detecting code used in digital networks and storage devices to detect accidental changes to raw data. CRC values are computed from a polynomial division of the input data.

Common CRC variants in IoT and embedded systems:

  • CRC-8: used in 1-Wire sensors, SMBus, and some BLE profiles
  • CRC-16/MODBUS: the standard checksum for Modbus RTU serial communication
  • CRC-16/CCITT-FALSE: widely used in HDLC, X.25, and Bluetooth HCI frames
  • CRC-32: the classic Ethernet and ZIP checksum, also used in BLE link-layer packets
  • CRC-32C: hardware-accelerated variant used in iSCSI and newer storage protocols

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