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RTD Calculator : Calculate temperature from resistance

RTD Conversion tool: R to T

This is used to calculate temperature value of RTD sensor from known resistance.

This calculation tool used to find out the temperature value of a RTD sensor with known resistance.


Resistive Temperature Detectors (RTDs) relate resistance to temperature by the following formula:

 RT = Rref[1 + α(T − Tref)]


RT = Resistance of RTD at given temperature T (ohms)
Rref = Resistance of RTD at the reference temperature Tref (ohms)
α = Temperature coefficient of resistance (ohms per ohm/degree)


The following example shows how to use this formula to calculate the resistance of a PT100 RTD with a temperature coefficient value of 0.00392 at a temperature of 35 degrees Celsius:

Assuming Temperature Reference = 0 Degrees

For PT100 RTD the Rref = 100

RT = 100 Ω[1 + (0.00392)(35 − 0)]

RT = 100 Ω[1 + 0.1372]

RT = 100 Ω[1.1372]

RT = 113.72 Ω

For Temperature to Resistance conversion also the same above formula applies.

The above given is a basic equation only for RTD calculation.


1.The above RTD calculation tool designed for a standard PT100 sensor.

2.If you are interested to calculate for a different RTD then change the fixed constant values as per the sensor type.

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Anonymous April 13, 2015 at 6:34 pm

Excellent Work Dude…. Thanks for sharing

C RamMohan April 20, 2015 at 4:54 am

Its a great instrumentation tool.

Dayanand November 12, 2015 at 4:46 pm

its great bt plz send mi various formula sits in excel type file on my mail id

dheeraj dhawas February 27, 2016 at 3:35 am

Dear sir,
tell me how u have calculate temperature coeff. Value of resistance.

S Bharadwaj Reddy February 27, 2016 at 5:22 am

Hello Dheeraj, For Temperature Coefficient Value – Pl Click here to Read


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