Thermocouple Types — Complete Comparison
Side-by-side specifications for all nine standardized thermocouple types. Covers temperature range, conductors, sensitivity, tolerance classes, atmosphere compatibility, and ASTM standards.
Tolerance CalculatorMaster Comparison Table
| Type | Positive (+) | Negative (−) | Range (Standard) | Max Continuous | Sensitivity ~25°C | Std Tolerance | Spl Tolerance | ASTM Standard | Category |
|---|---|---|---|---|---|---|---|---|---|
| J | Iron (Fe) | Constantan (Cu-Ni) | −40 to +750°C | 750°C | ~51.7 µV/°C | ±2.2°C or ±0.75% | ±1.1°C or ±0.4% | E230 | Base Metal |
| K | Chromel (Ni-Cr) | Alumel (Ni-Al) | −200 to +1260°C | 1260°C | ~40.6 µV/°C | ±2.2°C or ±0.75% | ±1.1°C or ±0.4% | E230 | Base Metal |
| T | Copper (Cu) | Constantan (Cu-Ni) | −200 to +370°C | 370°C | ~40.6 µV/°C | ±1.0°C or ±0.75% | ±0.5°C or ±0.4% | E230 | Base Metal |
| E | Chromel (Ni-Cr) | Constantan (Cu-Ni) | −200 to +870°C | 870°C | ~58.7 µV/°C | ±1.7°C or ±0.5% | ±1.0°C or ±0.4% | E230 | Base Metal |
| N | Nicrosil (Ni-Cr-Si) | Nisil (Ni-Si) | −200 to +1260°C | 1260°C | ~25.9 µV/°C | ±2.2°C or ±0.75% | ±1.1°C or ±0.4% | E230 | Base Metal |
| R | Pt-13%Rh | Pure Platinum | 0 to +1480°C | 1480°C | ~10.0 µV/°C | ±1.5°C or ±0.25% | ±0.6°C or ±0.1% | E1751 | Noble Metal |
| S | Pt-10%Rh | Pure Platinum | 0 to +1480°C | 1480°C | ~10.0 µV/°C | ±1.5°C or ±0.25% | ±0.6°C or ±0.1% | E1751 | Noble Metal |
| B | Pt-30%Rh | Pt-6%Rh | +600 to +1700°C | 1700°C | ~1.0 µV/°C @ 50°C | ±0.5% (≥600°C) | ±0.25% (≥600°C) | E1751 | Noble Metal |
| C | W-5%Re | W-26%Re | 0 to +2315°C | 2315°C | ~16.0 µV/°C | ±4.5°C or ±1.0% | ±2.3°C or ±0.5% | E696 | Refractory |
Atmosphere & Environment Compatibility
✓ Suitable · ⚠ Limited/conditional · ✗ Not recommended
| Type | Oxidizing | Reducing | Vacuum | Inert | Sulfurous | Moist H₂ | Cryogenic | Max Recommended |
|---|---|---|---|---|---|---|---|---|
| J | ⚠ <550°C | ✓ | ✓ | ✓ | ✗ | ✗ | ⚠ −40°C | 750°C |
| K | ✓ | ✗ | ⚠ | ✓ | ✗ | ✗ | ✓ | 1260°C |
| T | ✓ | ✓ | ✓ | ✓ | ✗ | ✓ | ✓ −270°C | 370°C |
| E | ✓ | ⚠ | ✓ | ✓ | ✗ | ✗ | ✓ | 870°C |
| N | ✓ | ⚠ | ✓ | ✓ | ✗ | ✗ | ✓ | 1260°C |
| R | ✓ | ✗ | ⚠ | ✓ | ✗ | ✗ | ✗ | 1480°C |
| S | ✓ | ✗ | ⚠ | ✓ | ✗ | ✗ | ✗ | 1480°C |
| B | ✓ | ✗ | ⚠ | ✓ | ✗ | ✗ | ✗ | 1700°C |
| C | ✗ Never | ✗ | ✓ | ✓ | ✗ | ✗ | ✗ | 2315°C |
ANSI & IEC Color Code Reference
ANSI = US standard (ASTM E230). IEC = International (IEC 60584). The negative conductor is always Red in ANSI.
| Type | ANSI (+) | ANSI (−) | ANSI Overall | IEC (+) | IEC (−) | IEC Overall |
|---|---|---|---|---|---|---|
| J | White | Red | Black | Black | White | Black |
| K | Yellow | Red | Yellow | Green | White | Green |
| T | Blue | Red | Blue | Brown | White | Brown |
| E | Purple | Red | Purple | Violet | White | Violet |
| N | Orange | Red | Orange | Pink | White | Pink |
| R | Black | Red | Green | Orange | White | Orange |
| S | Black | Red | Green | Orange | White | Orange |
| B | Gray | Red | Gray | Gray | White | Gray |
| C | White | Red | White | — | — | — |
Detailed Type Reference Pages
Type J
−40 to +750°C
Iron / Constantan. Reducing & vacuum atmospheres.
Type K
−200 to +1260°C
Chromel / Alumel. Most widely used general-purpose type.
Type T
−270 to +370°C
Copper / Constantan. Best for cryogenic applications.
Type E
−270 to +870°C
Chromel / Constantan. Highest EMF output, non-magnetic.
Type N
−270 to +1260°C
Nicrosil / Nisil. Improved stability over Type K.
Type R
0 to +1480°C
Pt-13%Rh / Pt. Noble metal, high temperature.
Type S
0 to +1480°C
Pt-10%Rh / Pt. ITS-90 gold point reference standard.
Type B
+600 to +1700°C
Pt-30%Rh / Pt-6%Rh. Highest noble metal temperature.
Type C — W5Re / W26Re
0 to +2315°C
Tungsten-Rhenium. Highest temperature of all types. Vacuum/inert only.