EMBEDDED TOOL
CRC Checksum Calculator
Compute CRC-8, CRC-16, or CRC-32 checksums over text or hex bytes.
Checksum (hex)
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Decimal
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Binary
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About this tool
Compute a CRC checksum (CRC-8, CRC-16/CCITT-FALSE, CRC-16/MODBUS, or CRC-32) over text or raw hex bytes — the same kind of error-detecting checksum used in serial protocols, firmware update files, and embedded communication frames.
Everything is computed locally in your browser — nothing is uploaded.
Frequently asked questions
- Why do different tools give different CRC-16 results for the same data?
- "CRC-16" isn't one algorithm — different variants (CCITT-FALSE, MODBUS, XMODEM, etc.) use different polynomials, initial values, and bit-reflection settings, all producing different checksums from the same input. Make sure you match the exact variant your protocol or device expects.
- What does "123456789" as the default input mean?
- It's the standard CRC check string used to verify an implementation — a correct CRC-32 implementation should produce 0xCBF43926 for the ASCII bytes "123456789", for example.
- What's the difference between the Text and Hex bytes input modes?
- Text mode encodes your input as UTF-8 bytes (so "AB" becomes the two bytes 0x41, 0x42). Hex bytes mode lets you specify raw byte values directly, like "41 42" or "4142", useful for testing binary protocol frames.