What is the difference between CRC-32 and CRC-32C?

CRC-32 uses the standard IEEE 802.3 polynomial (0xEDB88320) found in ZIP and PNG formats. CRC-32C uses the Castagnoli polynomial (0x82F63B78), which provides superior Hamming distance and error detection, widely utilized in iSCSI, SCTP, and modern filesystems.

Can I verify firmware or archive files offline?

Yes. Files dragged into the calculator are evaluated directly in your browser using streaming Web API buffers. No data is uploaded to any server.

Checksum Calculator & Verifier CRC & Adler

Calculate CRC-32, Castagnoli CRC-32C, CRC-16, Adler-32, and Fletcher checksums with instant validation.

📂

Drop file here or click to select

Computes checksums locally using zero server bandwidth

Verify Checksum:

CRC-32 (IEEE 802.3) ZIP, PNG, Ethernet

00000000

Poly: 0xEDB88320 Dec: 0

CRC-32C (Castagnoli) iSCSI, SCTP, Btrfs

00000000

Poly: 0x82F63B78 Dec: 0

Adler-32 RFC 1950, zlib

00000000

Mod: 65521 Dec: 0

CRC-16-CCITT X.25, V.41, Kermit

0000

Poly: 0x1021 Dec: 0

Fletcher-16 ITU-T / Network

0000

Mod: 255 Dec: 0

Fletcher-32 TCP Alternate Checksum

00000000

Mod: 65535 Dec: 0

Frequently Asked Questions

How does Adler-32 compare to CRC-32 in speed and reliability?

Adler-32 trades off some error detection capability on short messages in exchange for significantly faster computation, relying on two running 16-bit sums rather than bitwise polynomial division.

Are files processed securely without network transfer?

Yes. File reads take place directly in client RAM via the HTML5 File API. No telemetry or file chunks are transmitted to our servers.