Quality & Metrology worked example

Measurement Uncertainty with instrument or gauge uncertainty of 0.03 measured units: a worked example

What does the result look like when instrument or gauge uncertainty reaches 0.03 measured units? The full calculation is worked below with real intermediate numbers. Use it when building a simple uncertainty budget to compare measurement uncertainty against the tolerance you are verifying.

The inputs for this scenario

  • Instrument or gauge uncertainty: 0.03 measured units (raised for this scenario; the documented default is 0.01)
  • Repeatability (equipment) contribution: 0.01 measured units (unchanged)
  • Reproducibility (appraiser) contribution: 0.01 measured units (unchanged)
  • Environmental and other contribution: 0 measured units (unchanged)

Working through the calculation

  • Applying the documented formula (Total measurement uncertainty = instrument + repeatability + reproducibility + environmental) to the inputs above produces each figure below.
  • At this operating point the engine returns 0.05 units for total measurement uncertainty, the number this scenario is built around.
  • At this operating point the engine returns 0.03 units for element 1.
  • At this operating point the engine returns 0.01 units for element 2.
  • At this operating point the engine returns 0.01 units for element 3 + 4.

How this compares with the baseline

  • Against the tool's baseline example, where instrument or gauge uncertainty sits at 0.01 measured units and the headline result is 0.03 units, this scenario comes in 64.29% above the baseline at 0.05 units.
  • A figure at this level is achievable when instrument or gauge uncertainty is genuinely sustained, not just peaked for a shift. This tool sums contributors linearly, which is conservative; a rigorous GUM budget combines standard uncertainties in quadrature (root-sum-square) and applies a coverage factor, so this total will be larger than an RSS result.

Results at a glance

  • Total measurement uncertainty: 0.05 units (headline result)
  • Element 1: 0.03 units
  • Element 2: 0.01 units
  • Element 3 + 4: 0.01 units

Run it with your numbers

  • Every input above is editable in the live Measurement Uncertainty calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.