NTC Thermistor Calculator

The Beta model

An NTC thermistor's resistance falls exponentially with temperature:

$$R(T)=R_{25}{e}^{B\left(\frac{1}{T}-\frac{1}{T_{25}}\right)}$$

with temperatures in kelvin and $T_{25}=298.15\text{K}$. Solving for temperature gives

$$T={\left(\frac{1}{T_{25}}+\frac{\ln (R/R_{25})}{B}\right)}^{-1}$$

The Beta model is accurate to roughly ±1 °C over 0–70 °C; for wider ranges or tighter accuracy use the three-coefficient Steinhart–Hart equation from the manufacturer's datasheet.