Thermocouple Calculator

Thermocouple Calculator. A thermocouple is a temperature sensor that generates a small voltage — the Thermocouple Calculator converts between that voltage and the corresponding temperature for six common thermocouple types. Select your thermocouple type (K, J, T, E, B, or N), choose a calculation direction (mV → Temperature or Temperature → mV), enter your thermocouple voltage or temperature, set your temperature unit, and enter the ambient (cold junction) temperature for compensation. The calculator returns the calculated value along with the Seebeck coefficient, and the valid temperature and voltage ranges for your selected thermocouple type. Also try the RTD Calculator.

Thermocouple Type *

Calculate *

Thermocouple Voltage *

Temperature *

Temperature Unit *

Ambient Temperature (Cold Junction) *

°C

Reference junction temperature for compensation

Results

Calculated Value

Seebeck Coefficient

Temperature Range

Voltage Range

What is cold junction compensation in thermocouples?

Cold junction compensation accounts for the temperature at the reference junction where thermocouple wires connect to measurement equipment. Since thermocouple voltage depends on temperature difference, the cold junction temperature must be known for accurate measurements. See also our calculate Distance to Object, Distance (meters) & Sound Velocity — Ultrasonic Distance.

Which thermocouple type should I choose?

Type K is most common for general purpose (-200°C to 1260°C), Type J for industrial applications, Type T for low temperatures, Type E for high sensitivity, Type B for high temperatures, and Type N for improved stability over Type K.

What is the Seebeck coefficient?

The Seebeck coefficient (dV/dT) represents the thermocouple's sensitivity at a specific temperature, showing how much voltage changes per degree of temperature change. Higher values indicate greater sensitivity.

Why are thermocouple voltages measured in millivolts?

Thermocouples generate very small voltages, typically in the millivolt range. For example, a Type K thermocouple produces about 41 microvolts per degree Celsius, so measurements are expressed in millivolts for practical precision.

How accurate are NIST thermocouple tables?

NIST thermocouple reference tables are highly accurate, typically within ±0.1°C for most thermocouple types. These tables are the international standard for thermocouple calibration and temperature conversion.

Can I convert between different temperature units?

Yes, this calculator supports Celsius (°C), Fahrenheit (°F), and Kelvin (K) temperature units. The thermocouple voltage relationships remain consistent regardless of the temperature scale used for display.

What happens if I exceed the thermocouple's range?

Operating outside a thermocouple's specified temperature or voltage range can result in inaccurate readings, accelerated aging, or permanent damage. Always verify your application stays within the rated limits. You might also find our calculate Thermistor Resistance at Target Temperature useful.