Thermocouple Tolerances

American Limits of Error ASTM E230-ANSI MC 96.1

Temperature Range Tolerances-Reference Junction 0°C (32°F)
Thermocouple Type °C °F Standard Limit of Error Special Limit of Error
°C (Whichever is greater) °F °C (Whichever is greater) °F
T 0 to 370 32 to 700 +/-1 or +/-0.75% ² +/-0.5 or +/-0.4% ²
J 0 to 760 32 to 1400 +/-2.2 or +/-0.75% +/-1.1 or 0.4%
E 0 to 870 32 to 1600 +/-1.7 or +/-0.5% +/-1 or +/-0.4%
K or N 0 to 1260 32 to 2300 +/-2.2 or +/-0.75% +/-1.1 or +/-0.4%
R or S 0 to 1480 32 to 2700 +/-1.5 or +/-0.25% +/-0.6 or +/-0.1%
B 870 to 1700 1600 to 3100 +/-0.5% +/-0.25%

¹Tolerances in this table apply to new essentially homogeneous thermocouple wire, normally in the size range 0.25 to 33 mm in diameter (30 to 8 AWG) and used at temperatures not exceeding the recommended limits of upper temperature limits for protected thermocouples. If used at higher temperatures these tolerances may not apply.

²At a given temperature that is expressed in °C, the tolerance expressed in °F is 1.8 times larger than the tolerance expressed in °C. Note that wherever applicable, percentage-based tolerances must be computed from temperatures that are expressed in °C.

³Material is normally selected to meet tolerances above 0°C. If thermocouples are required to meet tolerances below 0°C, a special material selection step is usually required.