Fletcher Checksum Calculator

Supports the Fletcher-16/32/64 algorithms to calculate checksum values for text, hexadecimal data, or files, with support for batch processing and multi-format export.

Bug report

Browser execution mode: Your data is processed in your browser and is not uploaded to the server.

Speed and Stability: Processing speed depends on your device and browser. For large batch work, the desktop version may be more stable.

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If the online tool fails to load or run, try the desktop tool.https://tools.yikeaigc.com/

Tool Usage

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Set input, algorithm, and output format before calculating. Batch files show only the first 20; the exported ZIP includes all results.

Input data Enter text, hex data, or choose a file.

0 bytes

Text HEX File

Calculation settings Fletcher-16 is endian-independent; 32/64-bit versions use word grouping.

Algorithm Version

Fletcher-16 8-bit blocks, mod 255 Fletcher-32 16-bit blocks, mod 65535 Fletcher-64 32-bit blocks, mod 2^32-1

Text Encoding Byte order Incomplete tail word Output format HEX prefix Export Format

Bulk Results Waiting to calculate

Instructions

Software Usage Instructions

Select calculation mode: Single check is suitable for quickly calculating text, HEX, or a single file; batch file mode is suitable for processing multiple files at once.
Enter data: Text mode allows you to enter a string; HEX mode supports spaces, colons, commas, hyphens, and the 0x prefix; file mode allows you to select any type of file.
Set algorithm version: You can select one or more of Fletcher-16, Fletcher-32, and Fletcher-64 for simultaneous calculation.
Configure calculation parameters: You can set text encoding, byte order, how to handle incomplete trailing words, output format, and HEX prefix; when calculating Fletcher-32/64, make sure the endianness matches the target system.
Start calculation: Click “Calculate Checksum” to view the results. You can copy a single result or copy all results.
Batch export: Batch file mode displays the first 20 results, and the complete results can be exported as ZIP, CSV, JSON, or TXT.

FAQ

A: Fletcher-16 calculates using 8-bit data blocks and produces a 16-bit result; Fletcher-32 calculates using 16-bit data blocks and produces a 32-bit result; Fletcher-64 calculates using 32-bit data blocks and produces a 64-bit result. The larger the data block, the higher the number of result bits.

A: Fletcher-32 combines bytes into 16-bit data blocks, while Fletcher-64 combines them into 32-bit data blocks. Big-endian and little-endian byte orders form different data blocks, so the results may differ. The byte order must match the protocol documentation or the target device.

A: Continuous input such as 48656C6C6F is supported, as well as separators such as spaces, colons, commas, and hyphens, for example 48 65 6C, 48:65:6C, and 48-65-6C. The 0x prefix in the input is also automatically recognized.

A: To keep page browsing and operations smooth, the table only displays the first 20 results; the actual calculation processes all files, and exported CSV, JSON, TXT, or ZIP reports will also include the complete results.

A: They are suitable for protocol debugging, serial communication, file transfer verification, packet integrity checks, embedded data validation, and similar scenarios. If the scenario requires stronger error detection capabilities, algorithms such as CRC can also be evaluated together.