PT100 RTD Resistance to Temperature Calculator
Convert PT100 RTD resistance to temperature, or calculate expected resistance from temperature using the standard platinum RTD relationship.
How to use this calculator
- 1
Choose resistance-to-temperature or temperature-to-resistance.
- 2
Enter the measured resistance or temperature.
- 3
Calculate the corresponding PT100 value.
- 4
Compare with the instrument or calibration reading.
A PT100 resistance temperature detector has a nominal resistance of 100 Ω at 0 °C. Its resistance changes predictably with temperature, making PT100 sensors common in industrial process measurement and temperature transmitters.
This calculator is useful for calibration checks, RTD troubleshooting and verifying the expected sensor resistance before a temperature transmitter converts the signal to 4–20 mA or a digital value.
Formula and assumptions
Uses R₀ = 100 Ω and IEC 60751 coefficients A = 3.9083×10⁻³, B = −5.775×10⁻⁷ and C = −4.183×10⁻¹².
Examples and guidance
- At 0°C an ideal Pt100 measures 100 Ω.
- At 100°C an ideal Pt100 measures approximately 138.5055 Ω.
Continue your calculation
Move between related pressure, level, flow, signal and measurement calculations without starting a new search.
Questions and answers
What temperature range is supported?
The calculator supports the IEC 60751 Pt100 relationship from −200°C to 850°C.
Does it include lead-wire resistance?
No. Two-wire lead resistance, three-wire imbalance, self-heating and transmitter accuracy must be evaluated separately.
Can this be used for a Pt1000?
The relationship can be scaled for Pt1000, but this page is configured specifically for R₀ = 100 Ω Pt100 sensors.