Thermistor Beta Calculator Form
Enter two resistance-temperature points to calculate beta. Add optional values for a reference pair, target temperature, measured resistance, and graph range.
Plotly Graph
The chart plots thermistor resistance against temperature using the calculated beta model and the selected reference pair.
Example Data Table
| Example | R1 (Ω) | T1 (°C) | R2 (Ω) | T2 (°C) | Approx. Beta (K) |
|---|---|---|---|---|---|
| Common NTC sample | 10,000 | 25 | 3,265 | 50 | 3,957 |
| Higher beta sensor | 10,000 | 25 | 2,530 | 50 | 4,350 |
| Lower beta sensor | 10,000 | 25 | 3,700 | 50 | 3,650 |
Formula Used
β = ln(R1 / R2) / [(1 / T1) - (1 / T2)]
R(T) = R0 × exp[β × ((1 / T) - (1 / T0))]
T = 1 / [(1 / T0) + ln(R / R0) / β]
R∞ = R0 × exp(-β / T0)
Use Kelvin inside the formulas. This page converts the selected unit to Kelvin before calculation, then converts output values back to your chosen unit.
How to Use This Calculator
- Choose the temperature unit you want to enter.
- Enter two known resistance-temperature points for the thermistor.
- Optionally enter a reference resistance and reference temperature.
- Add a target temperature if you want predicted resistance.
- Add a measured resistance if you want estimated temperature.
- Set graph limits and point count for the plotted curve.
- Press Calculate Beta to show results above the form.
- Use the CSV and PDF buttons to export your calculation report.
Frequently Asked Questions
1) What is the beta value of a thermistor?
Beta is a material constant used to model how thermistor resistance changes with temperature. Larger beta values usually mean resistance changes more sharply as temperature changes.
2) Which thermistors use this beta model best?
This model is most commonly used for NTC thermistors over practical temperature ranges. It is simple, fast, and useful for many sensor and control calculations.
3) Why are temperatures converted to Kelvin?
The beta equations are defined with absolute temperature. Celsius and Fahrenheit must be converted to Kelvin first to keep the logarithmic and reciprocal temperature terms correct.
4) Why can beta become negative?
A negative beta often means the input points do not match a normal NTC trend, the values were reversed, or the sensor type is different from the model assumption.
5) What is the purpose of R0 and T0?
R0 and T0 define the reference point for prediction. If you leave them blank, the calculator uses the first known point as the reference pair automatically.
6) Is this the same as the Steinhart-Hart equation?
No. The beta model is simpler and uses fewer parameters. Steinhart-Hart is often more accurate over wider temperature ranges but requires additional coefficients.
7) What does the plotted graph show?
The graph shows the modeled resistance curve across the selected temperature range. It helps you visualize sensitivity, nonlinearity, and expected resistance values for design work.
8) Can I use this for electronics reports or lab sheets?
Yes. The page includes a summary report, graph, CSV export, and PDF export, making it useful for coursework, documentation, troubleshooting, and experiment records.