Adler-32 Hash Calculator
hash
All hashing runs in your browser. Data is never sent to any server.
Text Input
File Input
Drag & drop a file or click to select
1. How to Use
- Enter text or upload a file to calculate Adler-32 checksum.
- Click 'Generate Adler-32' for the 8-character hex result.
- Verify Adler32 checksums in the comparison section.
- Use for zlib stream or PNG Adler verification.
- Supports both text and file input.
2. How It Works
Adler-32 uses two 16-bit accumulators: A = 1 + Σ byte[i] (mod 65521), B = Σ (i+1)·byte[i] (mod 65521). Final checksum = B<<16 | A.
Optimized: A and B are updated incrementally. For each byte: A = (A + byte) mod 65521; B = (B + A) mod 65521. Modulo 65521 is prime (largest prime < 2¹⁶).
Adler-32 is simpler and often faster than CRC32. Used in zlib (with DEFLATE) for checksum. Not cryptographic.
PNG uses Adler-32 in the zlib-compressed data stream within IDAT chunks.
3. About Adler-32
Adler-32 is a 32-bit checksum designed by Mark Adler for zlib. It is faster than CRC32 but slightly less reliable for certain error patterns.
This Adler-32 checksum calculator computes Adler-32 for text and files. Used in zlib, PNG, and other compressed formats.
All processing runs in your browser.
4. Advantages
- Speed: Faster than CRC32 in many implementations.
- Simplicity: Easy to implement and understand.
- zlib/PNG support: Standard in DEFLATE-based formats.
- Small code: Minimal implementation footprint.
5. Real-World Use Cases
- zlib streams: Verify Adler-32 of DEFLATE-compressed data.
- PNG files: Adler-32 is part of PNG's compression layer.
- Quick checksums: When speed matters more than error detection strength.
- Legacy formats: Older protocols using Adler-32.