Home
Back
Relative Uncertainty Formula:
| From: | To: |
Relative Uncertainty (RU) is a measure of the uncertainty of a measurement compared to the size of the measurement itself. It is expressed as a ratio or percentage and provides insight into the quality of a measurement.
The calculator uses the Relative Uncertainty formula:
Where:
Explanation: The equation shows how significant the uncertainty is relative to the measured value. A smaller RU indicates a more precise measurement.
Details: Relative Uncertainty is crucial in scientific measurements as it allows comparison of measurement precision across different scales and units. It helps determine the reliability of experimental results.
Tips: Enter the absolute uncertainty (δx) and the measured value (x) in consistent units. Both values must be positive, and the measured value cannot be zero.
Q1: What's the difference between absolute and relative uncertainty?
A: Absolute uncertainty (δx) has the same units as the measurement, while relative uncertainty is dimensionless (or expressed as %) and shows the uncertainty relative to the measurement size.
Q2: What is a good relative uncertainty value?
A: This depends on the field, but generally <5% is acceptable for most applications, <1% is good, and <0.1% is excellent.
Q3: Can relative uncertainty be greater than 1 (100%)?
A: Yes, this indicates the uncertainty is larger than the measurement itself, suggesting very low measurement reliability.
Q4: How is relative uncertainty used in error propagation?
A: When combining measurements, relative uncertainties can be combined using specific rules depending on the mathematical operations involved.
Q5: Should I report relative uncertainty as decimal or percentage?
A: Both are valid. In scientific contexts, decimal form is often preferred, while percentages may be more intuitive for general audiences.