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CRC32 Calculator

Compute CRC32 and CRC32C checksums of any text or file without uploading a single byte.

Calculate a CRC32 checksum

CRC32: —
Decimal: —
CRC32C: —
Input: —
CRC32 uses the reflected polynomial of zip and gzip; CRC32C uses the Castagnoli polynomial of iSCSI and ext4.

How to use the CRC32 Calculator

  1. Type or paste the text you want to checksum.
  2. Or choose a file to compute its CRC32 instead.
  3. Read the hexadecimal, decimal and CRC32C values.

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Frequently Asked Questions

Common questions about the free online crc32 calculator.

CRC32 is a 32 bit cyclic redundancy check. It catches accidental changes in data very reliably, but it is not a cryptographic hash.
They use different polynomials. CRC32 comes from zip, gzip and Ethernet, while CRC32C uses the Castagnoli polynomial of iSCSI and ext4.
No. Anyone can recompute the checksum after editing the data, so CRC32 proves integrity against accidents, not against an attacker.
CRC32 produces a 32 bit value, which is exactly four bytes or eight hexadecimal digits, for example the well known cbf43926.
Choose the file and the tool reads it with FileReader, computes both CRC32 variants and shows the byte count of the input.
Compare the hexadecimal value, and check that the byte count matches too, since a different length always means different data.
No. Text and files are processed entirely in your browser and nothing is transmitted or stored.
Yes. It is completely free, works offline once loaded, and needs no account, no sign-up and no installation.

Last updated: October 10, 2026