Measurement Uncertainty Calculator (GUM Method)

Overview

Clause 7.6 requires laboratories to evaluate measurement uncertainty. This tool simplifies the “bottom-up” GUM approach.

Steps

1. Model Equation: Define the formula used to calculate the result (y = f(x1, x2…)).
2. Identify Sources: List all sources of uncertainty (u1, u2…).
   • Repeatability (Type A)
   • Calibration cert (Type B)
   • Resolution (Type B)
   • Drift (Type B)
   • Temp effects (Type B)
3. Quantify: Enter the value and distribution (Normal, Rectangular, Triangular) for each source.
4. Combine: The tool calculates the Combined Standard Uncertainty (uc).
5. Expand: Multiplies by k (usually 2) to get the Expanded Uncertainty (U) at 95% confidence.

Output

Provides a clear uncertainty budget table to include in your technical records.