v1.01 (AI Audited, 28/7/2025). Confirm suitability before use.
About RTD Temperature Sensors
Platinum Resistance Temperature Detectors (RTDs) are temperature sensors that operate on the principle that the electrical resistance of platinum changes predictably with temperature. The PT100 is a common type of RTD with a resistance of 100 ohms at 0°C.
This calculator implements the standard equations from IEC 60751 to convert between resistance and temperature for PT100 sensors.
Temperature to Resistance
Calculate the resistance of a PT100 RTD at a specific temperature.
Resistance to Temperature
Calculate the temperature corresponding to a specific RTD resistance.
Technical Information
Software Version 1.01 28/7/2025
IEC 60751 Standard Equations
For temperatures ≥ 0°C:
R(t) = R₀ × (1 + A×t + B×t²)
For temperatures < 0°C:
R(t) = R₀ × (1 + A×t + B×t² + C×(t-100)×t³)
Constants for PT100 RTDs
- R₀ = 100 Ω (resistance at 0°C)
- A = 3.9083 × 10⁻³ °C⁻¹
- B = -5.775 × 10⁻⁷ °C⁻²
- C = -4.183 × 10⁻¹² °C⁻⁴ (for t < 0°C)
Common RTD Resistance Values
| Temperature (°C) | PT100 Resistance (Ω) |
|---|---|
| -50 | 80.31 |
| -25 | 90.19 |
| 0 | 100.00 |
| 25 | 109.73 |
| 50 | 119.40 |
| 75 | 128.98 |
| 100 | 138.51 |
| 200 | 175.86 |
| 300 | 212.05 |
| 400 | 247.09 |