This application is a simple, fast, and comprehensive tool for field technicians, engineers and programmers to quickly and easily convert resistance to temperature and vice versa for many popular temperature sensing devices.

It includes support for over 70 types of RTDs (Resistance Temperature Detectors) and 9 types of popular Thermistors (Thermal Resistors). These devices exhibit predictable changes in their resistance depending on their ambient temperature, a characteristic that makes them useful for measuring temperature in many residential, commercial and industrial applications.

Merely select your entry mode (resistance in ohms or temperature in deg F or C) and your RTD or Thermistor type. Your entries are converted to the other two units instantly as you type.

The app supports:
Platinum RTDs – 56 combinations of reference resistance and alphas
Copper RTDs - 4 combinations of reference resistance and alphas
Nickel RTDs - 8 combinations of reference resistance and alphas
Nickel-Iron RTDs (Balco) - 6 combinations of reference resistance and alphas
Thermistors – 9 popular types including two types of 10K thermistors

Although the behavior of RTDs and Thermistors is predictable, they are not linear. This app uses the Steinhart-Hart formula for Thermistor calculations, the Callendar-Van Dusen formula for Platinum RTDs and similar algorithms for the other types of RTDs. All formulas and coefficients used by the app are described in the documentation provided with the app.

A number of lookup charts are included showing resistance vs temperature for many of the most popular types of RTDs.

The app uses 64-bit double precision math to provide the best possible resolution and accuracy for its calculations. However, since the algorithms are curve-fitting approximations, there will certainly be some points at which there are very small (usually insignificant) differences between the calculated values and a manufacturer’s published data table.

You can use the Settings application to change background colors and to adjust keyclick volume and change keyclick sounds.

Please send any comments, suggestions or corrections to

What’s New

Version 1.04

UI improvements for iOS7 compatibility
Added support for 15KΩ thermistors

Ratings and Reviews

Meldwin70 ,

RTD References

Nice ang useful application.


Dohmann Engineering Services
1.3 MB

Requires iOS 6.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Rated 4+
© 2011 Dohmann Engineering Services


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