Calculator Inputs
This page keeps a single-column flow, while the input area adapts to three columns on large screens, two on smaller screens, and one on mobile.
Example Data Table
| Parameter | Example Value |
|---|---|
| Reference Temperature | 100.0 °C |
| Readings | 99.8, 100.1, 99.9, 100.0, 100.2 |
| Calibration Correction | +0.15 °C |
| Instrument Resolution | 0.10 °C |
| Drift Uncertainty | 0.05 °C |
| Environmental Uncertainty | 0.08 °C |
| Full-Scale Range | 0 to 200 °C |
| Coverage Factor | 2 |
| Estimated Corrected Temperature | 100.15 °C |
| Estimated Overall Accuracy Band | ±0.393 °C |
Formula Used
- Mean measured temperature: \( \bar{x} = \frac{\sum x_i}{n} \)
- Corrected temperature: Corrected = Mean measured + Calibration correction
- Bias error: Bias = Corrected temperature − Reference temperature
- Absolute error: |Bias|
- Sample standard deviation: \( s = \sqrt{\frac{\sum (x_i-\bar{x})^2}{n-1}} \)
- Type A uncertainty: \( u_A = \frac{s}{\sqrt{n}} \)
- Resolution standard uncertainty: \( u_{res} = \frac{\text{resolution}}{\sqrt{12}} \)
- Combined standard uncertainty: \( u_c = \sqrt{u_A^2 + u_{res}^2 + u_{drift}^2 + u_{env}^2} \)
- Expanded uncertainty: \( U = k \times u_c \)
- Overall accuracy band: \( \pm (|Bias| + U) \)
- Error as percent of span: \( \frac{|Bias|}{\text{Full-scale span}} \times 100 \)
This approach combines correction, repeatability, display resolution, drift, and environmental effects into one engineering-focused estimate.
How to Use This Calculator
- Choose the working temperature unit.
- Enter the trusted reference temperature from a calibrated source.
- Enter one or more observed readings from the instrument under evaluation.
- Add the calibration correction from the latest calibration certificate.
- Enter resolution, drift uncertainty, and environmental uncertainty.
- Provide the full-scale minimum and maximum for span-based error reporting.
- Set the coverage factor, usually 2 for a practical expanded uncertainty estimate.
- Optionally enter an allowable tolerance to get a pass or fail decision.
- Click Calculate Accuracy to show the result below the header and above the form.
- Use the export buttons to download a CSV or PDF summary.
FAQs
1. What does this calculator measure?
It estimates how accurately a temperature instrument matches a trusted reference. It combines bias, repeatability, display resolution, drift, and environmental effects into one practical engineering result.
2. Why should I enter multiple readings?
Multiple readings reveal repeatability. The calculator uses them to compute standard deviation and Type A uncertainty, which improves the accuracy estimate over relying on one reading only.
3. What is calibration correction?
Calibration correction is the adjustment taken from a calibration certificate or known offset. It is added to the average measured value before bias and accuracy are evaluated.
4. Why is resolution divided by the square root of twelve?
That conversion treats rounding or digitization error as a rectangular distribution. It is a common uncertainty method for display resolution and least-count effects.
5. What does overall accuracy band mean?
It is the estimated maximum practical deviation around the corrected result, combining absolute bias and expanded uncertainty. It is reported as a plus-minus temperature value.
6. What is the difference between error and uncertainty?
Error is the observed difference from the reference. Uncertainty describes how much doubt remains in the result after considering repeatability, resolution, drift, and environmental effects.
7. When should I use a coverage factor of 2?
A coverage factor of 2 is commonly used for an approximate 95% expanded uncertainty. It is a practical default for many industrial and laboratory reporting tasks.
8. How is pass or fail determined?
The tool compares the overall accuracy band against the allowable tolerance. If the band is less than or equal to tolerance, the result passes; otherwise it fails.