CRC-32 checksum calculator
This calculator computes the CRC-32 checksum of text, the 32-bit error-detecting code used in ZIP archives, PNG images, gzip and Ethernet. Developers use it to check data integrity and to match checksums in file formats and protocols.
- Runs in your browser
- Free, no account needed
- Copy or download the result
Result
Example
The quick brown fox jumps over the lazy dog
CRC-32 (hex): 414fa339 CRC-32 (decimal): 1095738169 Bytes checked: 43
How to use the crc-32 checksum calculator
- Type or paste text into the Text box.
- Choose a Variant: CRC-32 (IEEE, ZIP and PNG) or CRC-32C (Castagnoli).
- Press Run to see the checksum in hex and decimal.
- Use Copy result to copy it.
How it works
Your text is encoded as UTF-8, and every byte is included in the checksum.
CRC-32 uses the reflected polynomial EDB88320 with a starting value and final XOR of FFFFFFFF. For the text 123456789 it gives cbf43926.
CRC-32C uses the Castagnoli polynomial 82F63B78, found in iSCSI, ext4 and some cloud storage APIs. For 123456789 it gives e3069283.
A CRC catches accidental changes such as flipped bits, but it is not a security hash and is easy to forge on purpose.
Everything runs in your browser. Your input is not uploaded or stored.
Questions and answers
What is a CRC32 checksum used for?
It detects accidental corruption. ZIP files, PNG chunks and gzip streams store a CRC-32 so a reader can tell if any bytes changed.
Can I use CRC32 for security?
No. Anyone can change data and adjust it so the CRC still matches. Use SHA-256 when tampering matters.
Why is there a decimal version?
Some programs and databases show the checksum as an unsigned 32-bit number instead of hex. Both are the same value.
Is my text uploaded?
No. It runs in your browser, and nothing you paste is sent to a server.