CRC Calculator

Compute CRC for HEX bytes or UTF-8 text using preset algorithms.
Supports CRC-8, CRC-16/IBM, CRC-16/CCITT-FALSE, CRC-32, and CRC-32C.

CRC Calculator Tool

Input

Tip: In auto mode, spaces, commas, and 0x prefixes are accepted.

Result

CRC (hex) —

CRC (dec) —

Bytes (BE) —

Bytes (LE) —

Notes: "Bytes (BE/LE)" shows the CRC value packed with the selected preset width. Reflected presets still show CRC value in regular hex format.

What CRC parameters mean

CRC compatibility depends on width, polynomial, init, refin, refout, and xorout. If one parameter differs, checksums can differ even for identical input bytes.

1) Choose preset

Pick the algorithm specified by your protocol or device documentation.

2) Enter data

Use HEX bytes or plain text (UTF-8). Auto mode handles common HEX notations.

3) Use output

Use CRC hex directly or the BE/LE byte order required by your packet format.

FAQ

Why is my CRC different from another calculator?

Common causes are parameter mismatch (poly/init/refin/refout/xorout), input parsing differences, and byte-order handling in transmitted packets.

When should I use CRC-32C instead of CRC-32?

Use whichever your protocol defines. Many modern systems use CRC-32C, while legacy protocols often require CRC-32 (ISO-HDLC).

Why does byte order matter for CRC output?

Protocols may transmit CRC bytes in big-endian or little-endian order. The numeric CRC value is the same, but the byte sequence on the wire can differ, which is why this tool shows both BE and LE.

What CRC parameters affect compatibility?

Width, polynomial, initial value, input/output reflection (refin/refout), and final xorout must all match the target protocol, or the checksum will not match even for identical input bytes.

What is the difference between CRC and a simple checksum?

A simple checksum (sum, XOR, or LRC) is faster to compute but detects fewer error patterns. CRC uses polynomial division, which catches most common bit-level transmission errors far more reliably.