Cloudesk

CRC Calculator

Calculate CRC checksums for 100+ algorithms (CRC-8 through CRC-64, Adler-32, Fletcher-16) with a parameterized BigInt engine

114 presets available

32-bitReflected
Checksum— CRC-32/ISO-HDLC (Ethernet/ZIP)

Enter input above to compute the checksum.

Normal vs. Reflected CRC

Normal (Non-Reflected)

Input bytes are processed MSB-first. The polynomial is applied without bit-reversal. Common in protocols like CRC-32/ISO-HDLC.

Reflected (Bit-Reversed)

Each input byte is reflected (bit-reversed) before processing, and the final register is also reflected. Used in Ethernet, Bluetooth, and ZIP files.

Summation Algorithms

Adler-32 and Fletcher-16 use modular addition rather than polynomial division. They are faster but offer weaker error detection than true CRC.

About CRC Checksums

What is CRC?

A Cyclic Redundancy Check (CRC) detects accidental changes to raw data. A sender computes a short fixed-size checksum and appends it; the receiver recomputes and compares.

Rocksoft Model Parameters

Width, Poly, Init, XorOut, RefIn, and RefOut fully define any CRC variant. The BigInt engine here supports widths from 1 to 64 bits.

CRC vs. Cryptographic Hash

CRC is designed for error detection, not security. Cryptographic hashes (SHA-256, MD5) are collision-resistant; CRC is not. Use SHA for security-sensitive checks.

How to Use the CRC Calculator

  1. 1Select a CRC algorithm from the preset list (e.g. CRC-32, CRC-16/MODBUS, Adler-32) using the dropdown picker.
  2. 2Toggle "Custom Parameters" to review or override the polynomial width, poly, init, XorOut, RefIn, and RefOut values for full algorithm control.
  3. 3Enter your input as plain text or paste hex bytes (e.g. FF A0 3C or 0xFF 0xA0 0x3C).
  4. 4The checksum is computed instantly and displayed in lowercase hex, uppercase hex, and Base64. Click Copy next to any format to copy it.

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