Looking for more advanced features like saving to your personal library and extended tools? Try the enhanced version at UncertaintyCalc.com — designed for calibration professionals who need more power and flexibility.
v1.01 (AI Audited, 28/7/2025). Confirm suitability before use.
About Measurement Uncertainty
Measurement uncertainty is a parameter associated with the result of a measurement that characterizes the dispersion of values that could reasonably be attributed to the measurand. This calculator follows the principles outlined in the Guide to the Expression of Uncertainty in Measurement (GUM).
Use this tool to calculate combined standard uncertainty and expanded uncertainty by adding individual uncertainty sources and their distributions.
Uncertainty Budget Calculator
Looking for more advanced features like saving to your personal library and extended tools? Try the enhanced version at UncertaintyCalc.com — designed for calibration professionals who need more power and flexibility.
Technical Information
Probability Distributions
- Normal (k=1): Standard uncertainty equals the entered value
- Rectangular: Standard uncertainty = Value ÷ √3
- Triangular: Standard uncertainty = Value ÷ √6
- Normal (k=2): Standard uncertainty = Value ÷ 2
Calculation Method
Combined standard uncertainty:
uc = √(Σ ui²)
Expanded uncertainty (k=2):
U = k × uc
Common Uncertainty Sources
- Reference standard uncertainty: From calibration certificate
- Resolution: Half of the smallest increment, typically with rectangular distribution
- Repeatability: Standard deviation of repeated measurements
- Environmental effects: Temperature, humidity, etc.
- Drift: Change in calibration over time