# RTD calculator

The basic functionality of an RTD such as a Pt100, is based on the principle that the resistance of a metal will increase or decrease in relation to temperature.

It follows that a temperature can be determined based on a specific resistance and vice versa.

Standards exist such as IEC 60751, which determines temperature/resistance profiles. These can then be used to determine a resistance value relevant to a particular temperature for example.

The calculator below is based on IEC 60751 profiles and can be used to calculate a resistance value based on a temperature input.

### Resistance calculator for platinum RTDs in conformance with IEC 60751

How to use the RTD resistance calculator:

1. Enter the RTD resistance at 0°C. (Most RTDs have a resistance of 100 ohms at 0°C).
2. Enter the RTD temperature in °C.

Resistance calculator for platinum RTDs in conformance with IEC 60751:

Callendar-Van Dusen equations:

RTD temperature ≥ 0°C: Rt = R0(1+At+Bt2)

RTD temperature < 0°C: Rt = R0[1+At+Bt2+C(t-100)t3]