CRC & Checksum Calculator

Calculate CRC-8, CRC-16, CRC-32, CRC-64 and Adler-32 for text, hex bytes or files.

Input

Encoded as UTF-8 exactly as typed, including spaces and line breaks. Text and hex input up to 16 MiB; files up to 1 GiB.

Options

Also known as CRC-32, CRC-32/V-42, PKZIP

Advanced

Output

Checksums appear here.

CRC and Adler-32 catch accidental corruption only. They do not authenticate data or resist deliberate tampering. Use the SHA-256 generator for integrity checks against tampering.

Enter text or hex bytes, or choose a file. Empty input is checked when you select Calculate.

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What it calculates

The calculator returns CRC-8/SMBUS, five common CRC-16 variants, CRC-24/OPENPGP, CRC-32/ISO-HDLC, CRC-32C (iSCSI), CRC-32/CKSUM, CRC-64/ECMA-182 and Adler-32 for the same bytes. Each result shows fixed-width uppercase hex, the exact decimal value and the full parameter set, so you can match it against a protocol specification or firmware log.

Choosing the right variant

A CRC is defined by its width, polynomial, initial value, input and output reflection and final XOR. "CRC-16" alone can mean ARC, MODBUS, XMODEM or several others, so presets use the full CRC RevEng catalogue names and show the check value for the ASCII string 123456789. If your device documents other parameters, enter them under Advanced as a custom CRC of 1 to 64 bits.

Text, hex bytes and files

Text is encoded as UTF-8 exactly as typed. Hex bytes accept spaces, colons, hyphens or one continuous string and reject odd digit counts instead of guessing. Files up to 1 GiB are read in slices inside a background worker with progress and Cancel, so the page stays responsive and the whole file is never loaded at once.

Not a security hash

CRCs and Adler-32 detect accidental errors such as bit flips or truncated transfers. Anyone can craft data with a chosen CRC, so use a cryptographic hash such as SHA-256 when you need to detect deliberate changes. All calculations run in your browser; nothing is uploaded or stored.

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