Thermocouple Calculator
Convert thermocouple millivolts to temperature and temperature back to millivolts for types J, K, and T using embedded NIST ITS-90 coefficients, with cold-junction compensation and a Pt100 RTD mode.
Sensor Conversion
Conversion Results
Temperature
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degrees Celsius
Temperature
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degrees Fahrenheit
Signal
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mV or Ω for sensor type
Formula Breakdown
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Informative Guides & Helper Articles
Best Practices for Thermocouple Measurement
Select sensors, handle cold junctions, manage lead wires, and keep calibration discipline for trustworthy thermocouple readings.
Read Article →Common Errors in Thermocouple Readings
Assumed types, uncalibrated cold junctions, and extension-wire mistakes that silently skew every thermocouple conversion.
Read Article →Future Trends in Thermocouple Measurement
Wireless sensing, edge computation, and recalibrated standards that are reshaping how process temperature is measured.
Read Article →Guide to Thermocouple mV Conversion
Understand the Seebeck effect, NIST ITS-90 polynomials, cold-junction compensation, and how J, K, and T thermocouples convert.
Read Article →How to Use the Thermocouple Calculator
Converts thermocouple voltages to temperatures and back using standardized tables for K, J, T, E, N types.
- Pick thermocouple type (K, J, T, E, N).
- Enter mV (or temperature for reverse); 0C reference standard.
- Read the interpolated temperature with range context.
Seebeck Voltage and Cold Junctions
Thermocouples exploit the Seebeck effect: two dissimilar metals produce voltage proportional to the temperature difference between junctions - K-type (chromel-alumel) ~41 uV/degC over -200 to +1,260C; J-type higher output but rust-prone above ~750C; T-type best for cryogenics. Two practices decide accuracy: cold-junction compensation (tables assume 0C reference; your meter compensates - bad CJC is the #1 error) and extension polarity (reversed leads read shifted by ambient). Nonlinearity is why tables exist: K-type sensitivity swings 35-44 uV/degC across range.
Thermocouple Calculator FAQ
How does a thermocouple work?
Seebeck effect: two dissimilar metals generate voltage proportional to junction temperature difference.
What is cold junction compensation?
Tables assume a 0C reference; meters measure their terminals and compensate. Poor CJC is the most common error.
Which type should I use?
K general to 1260C; J higher output, dry use; T cryogenic; E highest output; N stability at high temps.