Adler-32 Generator
Generate the Adler-32 checksum of any text instantly using a pure JavaScript implementation, verified against the standard's published test vectors.
Adler-32 checksum will appear here...
How to Use the Adler-32 Generator
Type or paste any text into the input box — the Adler-32 checksum is computed live and shown as an 8 hex character value. Adler-32 keeps two running sums as it processes each byte: a simple sum of all bytes (plus 1), and a running sum of that first sum, both taken modulo the prime 65521. The two 16-bit sums are then combined into a single 32-bit checksum by placing the second sum in the high 16 bits and the first sum in the low 16 bits.
A = (1 + Σ byte) mod 65521 | B = (Σ A) mod 65521 | Checksum = (B << 16) | A
Example
Hashing the text Wikipedia produces the checksum 11e60398, a widely published Adler-32 reference value.
Common Use Cases
- Quickly detecting accidental data corruption in a file or data stream (as used inside zlib and PNG-related tooling).
- Comparing two versions of a text block for equality without a full byte-by-byte diff.
- Learning how a fast, non-cryptographic checksum algorithm works compared to cryptographic hash functions.
FAQs
- Is Adler-32 a cryptographic hash? No — Adler-32 is a simple checksum designed for fast error detection, not security. It is not resistant to intentional tampering and should never be used for password storage, digital signatures, or any security-sensitive purpose. Use SHA-256 or SHA-512 for those.
- How is Adler-32 different from a CRC checksum? Both are fast, non-cryptographic checksums used for error detection, but they use different mathematical constructions. Adler-32 is generally faster to compute in software than CRC-32, though CRC-32 offers somewhat stronger error-detection guarantees for certain error patterns — Adler-32 is famously used inside the zlib compression library specifically for its speed.
- Is my text uploaded anywhere? No — the checksum is computed entirely client-side in your browser. Nothing you type is sent to a server.