Compute the CRC-32 checksum of text.
Calculated locally in your browser.
How do you calculate a CRC-32 checksum?
CRC-32 processes each byte through a polynomial-division algorithm (polynomial 0xEDB88320, reflected), seeded at 0xFFFFFFFF and finally inverted. It is a fast checksum that reliably catches accidental data changes, used in ZIP, PNG and Ethernet, but it is not cryptographic. For example, the string "123456789" has a CRC-32 of 0xCBF43926.
Understanding your result
A CRC (cyclic redundancy check) is a fast checksum that reliably catches accidental changes in data, which is why it is used in storage and network formats. It is not a cryptographic hash and must not be used for security.
Formula and method
CRC-32 processes each byte through a polynomial-division algorithm (polynomial 0xEDB88320, reflected) seeded at 0xFFFFFFFF and finally inverted.
Assumptions and limitations
This computes the standard CRC-32 used by ZIP, PNG and Ethernet, seeded and inverted per that variant, over the text you enter treated as UTF-8 bytes. It is an error-detecting checksum, not a cryptographic hash, so identical inputs always match but it offers no security; other CRC-32 variants will produce different values.
Worked example
The string “123456789” has a CRC-32 of 0xCBF43926.
How to use this tool
- Paste or type your text.
- Read the CRC-32 in hex and decimal.
- Copy the value.
Common mistakes to avoid
- Using CRC-32 for security or passwords — it is not cryptographic.
- Comparing against a checksum computed with different text encoding.
About the CRC32 Checksum Calculator
The CRC32 Checksum Calculator computes the CRC-32 (IEEE 802.3) checksum of your text — the same algorithm used by ZIP, PNG and Ethernet — and shows it in hexadecimal and decimal.
Who should use this tool
Developers verifying data integrity and debugging file formats.
Benefits
- Standard CRC-32 (IEEE 802.3).
- Result in hex and decimal.
- Works on the UTF-8 bytes of your text.
- Runs locally — nothing is uploaded.
Practical use cases
- Checking a file or data checksum.
- Verifying transmitted data is unchanged.
- Debugging ZIP or PNG CRC values.
Explore all Developer Tools tools
Frequently asked questions
Is CRC-32 secure?
No. It detects accidental errors but is easy to forge deliberately. Use SHA-256 or similar for security.
Which CRC-32 variant is this?
The standard IEEE 802.3 CRC-32 used by ZIP, gzip, PNG and Ethernet.
Can I use CRC-32 to check that a file was not tampered with?
Only against accidental corruption, not deliberate tampering. CRC-32 reliably catches random transmission or storage errors, which is why formats like ZIP and PNG use it, but it is easy to forge a matching checksum on purpose. For integrity against attackers, use a cryptographic hash such as SHA-256 instead.