CRC32 Calculator
Compute CRC32 checksums, matching zip and gzip
What is CRC32 Calculator?
This CRC32 tool computes the 32-bit cyclic redundancy check defined by the IEEE 802.3 polynomial and shows it in both hexadecimal and decimal. It detects accidental corruption during transfer or storage and uses the same algorithm as zip, gzip, and PNG. Computation happens locally.
How to use CRC32 Calculator
- 1Enter your text content.
- 2Read off the hexadecimal and decimal results.
- 3Compare them against the checksum you were given.
Frequently asked questions
How is CRC32 different from a hash function?+
CRC32 is an error-detecting code designed to catch random corruption. It is extremely fast but offers no resistance to deliberate tampering — forging content with a matching CRC32 is trivial. Use it to spot accidental damage only, never as a security check.
Why does another tool give me a different CRC32 value?+
Several CRC variants exist, and the polynomial, initial value, and whether input and output are reflected all change the result. This tool implements CRC-32/ISO-HDLC, the variant zip uses. If your values disagree, check whether the other side is using CRC-32C (Castagnoli) or another variant.
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