CRC & Checksum Calculator
Calculate IEEE CRC-32, Castagnoli CRC-32C, CRC-16-CCITT, CRC-16-Modbus, and Adler-32 checksums for text and files.
Private by architecture:
All processing is 100% client-side memory. Your data never leaves this browser tab.
Quick Presets:
Text Input or File Drop
Calculated Checksums
CRC-32 (IEEE 802.3)
0x00000000
Dec: 0
CRC-32C (Castagnoli)
0x00000000
Dec: 0
CRC-16-CCITT (XModem)
0x0000
Dec: 0
CRC-16-Modbus (Industrial)
0x0000
Dec: 0
Adler-32 (RFC 1950 zlib)
0x00000000
Dec: 0
About This Tool
Compute standard cyclic redundancy checks and cryptographic checksums directly in your browser without uploading files across the network.
Supports IEEE 802.3 CRC-32, Castagnoli CRC-32C (iSCSI/Btrfs standard), CRC-16-CCITT, industrial CRC-16-Modbus, and RFC 1950 Adler-32.
Features instant checksum verification to compare computed hashes against expected supplier checksums with zero server egress.
Key Features
- Standard CRC-32 & CRC-32C: Generate standard IEEE 802.3 and Castagnoli checksums for data integrity verification.
- Industrial CRC-16 Algorithms: Compute CRC-16-CCITT (XModem/Kermit) and reflected CRC-16-Modbus.
- Adler-32 zlib Checksum: Compute fast rolling checksums compliant with RFC 1950 zlib data compression.
- File & String Support: Drag and drop any binary file or paste raw text to inspect byte-level checksums.
Frequently Asked Questions
What is the difference between CRC-32 and CRC-32C?
CRC-32 uses the standard IEEE 802.3 polynomial (0xEDB88320), commonly found in ZIP archives and Ethernet frames. CRC-32C uses the Castagnoli polynomial (0x82F63B78), which offers superior error detection characteristics and has hardware acceleration in modern x86 (SSE4.2) and ARM processors.
Is CRC a cryptographic hash function?
No. Cyclic Redundancy Checks are error-detecting codes designed to catch accidental data corruption in storage and network transmission. They are not cryptographically secure against intentional tampering. Use SHA-256 or SHA-512 for security.
Are my uploaded files sent to an external server?
No. Files are read as local byte arrays via the browser HTML5 FileReader API and processed 100% locally in memory.
