Skip to content
en
All tools

Categories

Developer ToolsEncoding & DecodingJSON & DataHash & ChecksumText ToolsDate & TimeNetwork ToolsFile ToolsMarkdown & Diagrams

CRC32 & Adler-32 Calculator

Compute a CRC-32 (IEEE 802.3) or Adler-32 checksum and read it as hex, decimal or Base64.

Processed locally in your browser

Options
0 chars · 0 lines
The result will appear here.

What is CRC32 & Adler-32 Calculator?

A CRC is a short checksum designed to catch accidental errors such as flipped bits in a download, a network frame or a stored file. CRC-32 (IEEE 802.3, the variant used by ZIP, PNG, gzip and Ethernet) produces 32 bits, shown as 8 hex characters. Adler-32, used by zlib, is cheaper to compute but weaker on short inputs.

The tool encodes your text as UTF-8 (or reads hex bytes), computes the chosen checksum and shows it as hex and as an unsigned decimal number. The CRC-32 of "123456789" is cbf43926, the standard check value.

How does it work?

  1. Pick CRC-32 or Adler-32.
  2. Type text or paste hex bytes (change the input type to hex).
  3. Read the checksum in hex, decimal or Base64 in the result panel.

Common use cases

  • Verifying the CRC-32 stored in a ZIP entry or a PNG chunk.
  • Debugging a protocol or file format that carries a CRC-32 field.
  • Getting a quick hash for a hash-table bucket or change detection on small strings.
  • Cross-checking your own CRC implementation against the standard check value.

Examples

Try this input in the tool above:

Input
The quick brown fox jumps over the lazy dog
Output
414fa339

Privacy

CRC32 & Adler-32 Calculator runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.

Limitations

CRC and Adler-32 detect accidental corruption only: they are trivial to forge and offer no protection against tampering. Use SHA-256 for integrity against an attacker.

Frequently asked questions

Is CRC32 a secure hash?

No. It is linear and easy to manipulate: an attacker can craft data with any CRC they want. It is only meant to catch random errors.

Why do different tools show different CRC32 values?

There are several CRC-32 variants (IEEE, Castagnoli/CRC-32C, BZIP2…). This tool uses the IEEE 802.3 variant found in ZIP, PNG and gzip.

How can I read the decimal value?

It is shown in the result rows as an unsigned 32-bit integer, for example 891568578 for "abc".

Related tools

More tools in Hash & Checksum →