Type N thermocouple table: mV vs °C (−270 to 1300 °C)

Type N thermocouple voltage in mV from −270 to 1300 °C in 10 °C steps, from the NIST (ITS-90) reference functions with the reference junction at 0 °C.

A type N thermocouple (nickel-chromium-silicon (+) and nickel-silicon (−)) produces a voltage that depends on the temperature difference between the measuring junction and the reference junction. The table follows the NIST (ITS-90) reference functions, with the reference junction at 0 °C.

Type N thermocouple, reference junction at 0 °C: −270 … 140 °C
°C	mV
−270	−4.345
−260	−4.336
−250	−4.313
−240	−4.277
−230	−4.226
−220	−4.162
−210	−4.083
−200	−3.990
−190	−3.884
−180	−3.766
−170	−3.634
−160	−3.491
−150	−3.336
−140	−3.171
−130	−2.994
−120	−2.808
−110	−2.612
−100	−2.407
−90	−2.193
−80	−1.972
−70	−1.744
−60	−1.509
−50	−1.269
−40	−1.023
−30	−0.772
−20	−0.518
−10	−0.260
0	0.000
10	0.261
20	0.525
30	0.793
40	1.065
50	1.340
60	1.619
70	1.902
80	2.189
90	2.480
100	2.774
110	3.072
120	3.374
130	3.680
140	3.989

Type N thermocouple, reference junction at 0 °C: 150 … 560 °C
°C	mV
150	4.302
160	4.618
170	4.937
180	5.259
190	5.585
200	5.913
210	6.245
220	6.579
230	6.916
240	7.255
250	7.597
260	7.941
270	8.288
280	8.637
290	8.988
300	9.341
310	9.696
320	10.054
330	10.413
340	10.774
350	11.136
360	11.501
370	11.867
380	12.234
390	12.603
400	12.974
410	13.346
420	13.719
430	14.094
440	14.469
450	14.846
460	15.225
470	15.604
480	15.984
490	16.366
500	16.748
510	17.131
520	17.515
530	17.900
540	18.286
550	18.672
560	19.059

Type N thermocouple, reference junction at 0 °C: 570 … 980 °C
°C	mV
570	19.447
580	19.835
590	20.224
600	20.613
610	21.003
620	21.393
630	21.784
640	22.175
650	22.566
660	22.958
670	23.350
680	23.742
690	24.134
700	24.527
710	24.919
720	25.312
730	25.705
740	26.098
750	26.491
760	26.883
770	27.276
780	27.669
790	28.062
800	28.455
810	28.847
820	29.239
830	29.632
840	30.024
850	30.416
860	30.807
870	31.199
880	31.590
890	31.981
900	32.371
910	32.761
920	33.151
930	33.541
940	33.930
950	34.319
960	34.707
970	35.095
980	35.482

Type N thermocouple, reference junction at 0 °C: 990 … 1300 °C
°C	mV
990	35.869
1000	36.256
1010	36.641
1020	37.027
1030	37.411
1040	37.795
1050	38.179
1060	38.562
1070	38.944
1080	39.326
1090	39.706
1100	40.087
1110	40.466
1120	40.845
1130	41.223
1140	41.600
1150	41.976
1160	42.352
1170	42.727
1180	43.101
1190	43.474
1200	43.846
1210	44.218
1220	44.588
1230	44.958
1240	45.326
1250	45.694
1260	46.060
1270	46.425
1280	46.789
1290	47.152
1300	47.513

What about the cold junction?

In the field the reference junction sits at the transmitter or instrument terminals, almost never at 0 °C. So the voltage measured at the terminals is not the table value: the instrument compensates the cold junction. To check a mV reading, take the terminal temperature into account.

Calculated reference values, not measurements. The thermocouple tolerance depends on its class (IEC 60584-1) and is not in the table.

Values calculated from the reference functions; they do not replace measurement or a calibration certificate.

What about the cold junction?

See also