> tools / crc

CRC calculator.

Check text, bytes, or a selected file range against a known algorithm.

Inputs stay on your device

01Input

Input format

Input data

UTF-8 includes spaces and newlines. Limit: 1 MiB of bytes.

9 bytes · limit 1 MiB

Byte offset

Byte length

Decimal or 0x HEX byte counts. Blank length uses all remaining bytes; zero calculates the CRC of an empty range. Offset + length must fit the input.

CRC preset

CRC variants differ in their polynomial, initial value, reflection, and final XOR. Match every parameter to your firmware or protocol.

The reference input is ASCII 123456789 (no newline). CRC-32 / ISO-HDLC returns 0xCBF43926.

File ranges use absolute byte offsets. The range contains exactly the selected bytes, without file-format decoding, padding, or a terminating NUL.