What Fletcher-16 Calculator does
Calculate the two-sum Fletcher-16 checksum over UTF-8 text with modulo-255 accumulation.
Input and output contract
Text is UTF-8 encoded before checksum calculation. A 4-digit uppercase hexadecimal checksum.
Safe workflow
Enter text and calculate only when the target format specifies Fletcher-16 semantics. SaveEditor processes this operation locally in the browser and does not infer a game format from the input.
Important limitations
Fletcher variants and byte-order conventions can differ; this Tool returns the conventional sum2-high, sum1-low hexadecimal value. If expected bytes differ, verify whether the format stores the two checksum bytes in reverse order.