CRC32 Checksum Generator

The CRC32 Checksum Generator computes the CRC-32 checksum of any text or file. Type or paste text, or upload a file, and the tool returns an 8-digit uppercase hexadecimal value — the same checksum format used by zip archives, gzip compression, and PNG images.

CRC-32 (Cyclic Redundancy Check, 32-bit) is not a cryptographic hash — it's designed to catch accidental data corruption (a flipped bit during a transfer or a truncated download), not to resist deliberate tampering. It's fast, has a short fixed-length output, and is built into countless file formats and network protocols, which is why it remains a useful general-purpose integrity check.

How to use it

1. Enter your text in the input box, or upload a file using the uploader above it.
2. The CRC-32 checksum appears instantly as an 8-digit uppercase hex value (e.g. CBF43926).
3. Use the copy or download button to save the result.

Uploading a file fills the same text box with its contents, so you only ever need one input — paste text directly, or drop a file to check it instead.

Which polynomial does this use?

This tool computes the standard CRC-32 defined by IEEE 802.3, using the (reversed) polynomial 0xEDB88320. It's the variant used by zip, gzip, PNG, Ethernet frame checking, and most "CRC32" checksum utilities you'll find elsewhere — if another tool's CRC-32 doesn't match this one, double-check it isn't computing CRC-32C (Castagnoli, used by iSCSI and ext4) or including a different byte encoding of your text.

Why doesn't my file's CRC32 match this tool's output for the same text?

Text encoding matters. This tool encodes text as UTF-8 before hashing, so pasting the same characters that were saved in a file with a different encoding (UTF-16, Latin-1) will produce a different checksum, even though the characters look identical on screen. Binary files aren't affected by this, since a CRC-32 of file bytes doesn't involve text encoding at all.

Is CRC-32 secure enough for verifying downloads or passwords?

No. CRC-32 is trivial to forge — an attacker can construct a different file with the same checksum in seconds. It's suitable for detecting accidental corruption, not for verifying authenticity or storing passwords. For security-sensitive integrity checks, use a cryptographic hash like SHA-256 (see the Hash Generator).

What's the CRC-32 of an empty input?

00000000. An empty message has nothing to checksum, so the algorithm returns its initial value unchanged.

Privacy

Everything runs entirely in your browser. Your text or file is never uploaded to a server — the checksum is computed locally and only the result you choose to copy or download ever leaves your device.