What this calculator does
Perform arithmetic and round the result using significant-figure rules.
How it works
The calculator evaluates multiplication/division retain the fewest significant figures; addition/subtraction retain the fewest decimal places. Inputs are checked before calculation, and invalid values such as zero denominators or out-of-range selections produce a clear error instead of a misleading result.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
3-
?operation=OperationChoice · Required · Default: multiply · Accepted values: add, subtract, multiply, divide
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?valueA=First measured valueText · Required · Default: 12.30
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?valueB=Second measured valueText · Required · Default: 4.5
Outputs
4-
roundedResultResult with significant-figure ruleText · Primary output
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unroundedResultUnrounded numeric resultNumber
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ruleRule appliedText
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retainedDigitsRetained significant figuresWhole number
Inputs and results
The inputs are Operation, First measured value, Second measured value. Results include Result with significant-figure rule, Unrounded numeric result, Rule applied, Retained significant figures.