How to use the checksum calculator
Prepare the values for this calculation
Calculate an 8-bit additive checksum of UTF-8 input bytes. Use the formula below to check that it answers your question. Read the input units before transferring figures from a statement, measurement or dataset.
Enter and check each input
- Text: use the same separators and value order as the example in the input table. Replace the example data with your own complete dataset.
The input table gives a complete example. Keep units and time periods consistent across related fields.
Calculate and resolve any input error
Choose Calculate after entering the values. Changes also update the answer after a short pause. If an error appears, follow its message, correct the field and calculate again. Reset restores the example values.
Interpret the answer
Check 8-bit checksum first. With the unchanged example inputs, it is 0xE1. Interpret it using the formula and assumptions on this page.
Compare and keep a useful result
The result diagram shows the inputs, method and output. A numeric chart is shown only when the calculation supports a meaningful numeric relationship.
Use Copy result or Download CSV to keep the answer. Share tool shares the page address without placing your input values in the URL. Recheck inputs and assumptions before using the result for a decision.
Checksum Calculator formula
Checksum=Σ UTF-8 bytes mod 256.
Inputs and units
| Input | Format / range | Example |
|---|---|---|
| Text | Text / numeric list | SopidoCalc |
Worked example
Using the example inputs above, the 8-bit checksum is 0xE1.
- 8-bit checksum
- 0xE1
Results and assumptions
The output uses the 8-bit checksum convention and formula shown above. Match the entered units and source assumptions when comparing results.
Fix an input or unexpected result
If your answer differs from the example, choose Reset and compare every field, including selected units and options. Check percentage versus decimal entry and whether values describe the same period. Round only the final displayed answer when reproducing the formula.
If a discrepancy remains, report the calculator issue with the page address, non-sensitive example inputs, actual result, expected result and a reference for your calculation.