Fletcher-16 Checksum & Integrity Tool

Calculate 16-bit Fletcher checksums online with modular block arithmetic to verify data integrity and detect transmission errors in digital data.

How to Use Fletcher-16 Checksum & Integrity Tool

  1. Input Data String or Bytes: Enter the message string or hexadecimal bytes to checksum.
  2. Compute Running Modulo 255 Sums: Accumulates two running 8-bit sums over the data stream.
  3. Inspect 16-Bit Checksum Result: View the combined 16-bit integer and hexadecimal verification checksum.

Frequently Asked Questions

How is Fletcher-16 superior to a simple additive checksum?

Fletcher-16 is position-dependent. Swapping two adjacent bytes changes the second sum, allowing Fletcher-16 to detect transposition errors that standard byte addition misses.