Independent Measurement Uncertainty Calculator
Combine independent standard uncertainty contributions already expressed in result units.
Your result
MATHEnter your values and select calculate.
On this page How it works & practical examples
How to use the Independent Measurement Uncertainty Calculator
Enter non-negative standard uncertainty contributions in the same unit as the reported result. Sensitivity coefficients must already have been applied, so these are contributions to output uncertainty rather than arbitrary raw input tolerances.
The calculation
Worked example
Independent contributions 0.3 and 0.4 combine to 0.5. At k = 2, expanded uncertainty is 1 and a result of 100 is displayed with an interval from 99 to 101.
Assumptions and limits
Correlation and degrees of freedom are not inferred. A chosen k alone does not guarantee a stated confidence level. Systematic corrections and a justified measurement model must be considered separately.
Common questions
Can I enter manufacturer maximum errors directly?
Not automatically. Convert them to justified standard uncertainty contributions with a suitable distribution model first.
Does k = 2 always mean 95% confidence?
No. That interpretation needs additional distribution and uncertainty-estimation conditions.