Sparky tools
Thermocouple Converter
Convert millivolts to temperature and back, with cold junction compensation.
Data: Type J checked against NIST Monograph 175 (ITS-90). Other types not yet checked against it. About standard editions
For reference only. Based on IEC 60584 simplified tables with linear interpolation. Always verify against certified reference tables for critical measurements.
Thermocouple Converter
Thermocouple Type
Type K (Chromel / Alumel)|Range: -200°C to 1372°C|-5.891 to 54.886 mV|
Green/White
Conversion Mode
Input Values
Valid range: -5.891 to 54.886 mV
0°C = ice-point reference (ideal). Field conditions often 25°C.
Type K Reference Table
IEC 60584 reference values: Type K (Chromel / Alumel)
| Temp (°C) | mV |
|---|---|
| -200 | -5.891 |
| -150 | -4.913 |
| -100 | -3.554 |
| -50 | -1.889 |
| 0 | 0.000 |
| 50 | 2.023 |
| 100 | 4.096 |
| 150 | 6.138 |
| 200 | 8.138 |
| 250 | 10.153 |
| 300 | 12.209 |
| 350 | 14.293 |
| 400 | 16.397 |
| 450 | 18.516 |
| 500 | 20.644 |
| 550 | 22.776 |
| 600 | 24.905 |
| 650 | 27.025 |
| 700 | 29.129 |
| 750 | 31.213 |
| 800 | 33.275 |
| 850 | 35.313 |
| 900 | 37.326 |
| 950 | 39.314 |
| 1000 | 41.276 |
| 1050 | 43.211 |
| 1100 | 45.119 |
| 1150 | 46.995 |
| 1200 | 48.838 |
| 1250 | 50.644 |
| 1300 | 52.410 |
| 1372 | 54.886 |
Standard References
- IEC 60584-1, Thermocouples: EMF specifications and tolerances
- AS 1771, Colour coding: AU/NZ thermocouple identification
- ASTM E230: Standard specification for temperature-EMF tables
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Questions
- What is cold junction compensation?
- A thermocouple measures the difference between the hot junction and the point where its wires meet the instrument, the reference or cold junction. If that point is not at 0 °C, the millivolts read low by the value for that temperature. The tool adds that value back before it converts.
- What reference junction temperature do I enter?
- The temperature at the terminals where the thermocouple or its extension cable lands, usually the transmitter or the instrument. Leave it at 0 °C for the plain table values.
- How accurate is the conversion?
- The tool draws a straight line between reference points taken from the IEC 60584 tables. That is good enough to check a reading or a loop. For calibration work, use the full reference tables or your calibrator.
- Which thermocouple types does it cover?
- Types K, J, T, E, N, R, S and B. Each has its own range, for example Type K from -200 to 1372 °C and Type T from -200 to 400 °C. A value outside the range shows a warning instead of a result.
- How do I simulate a temperature with a millivolt source?
- Switch to temperature to millivolts and enter the temperature and the reference junction temperature. The compensated figure takes off the reference junction millivolts. That is what an instrument with cold junction compensation expects at its terminals.