Type R thermocouple table: mV vs °C (−50 to 1768.1 °C)

Type R thermocouple voltage in mV from −50 to 1768.1 °C in 10 °C steps, from the NIST (ITS-90) reference functions with the reference junction at 0 °C.

A type R thermocouple (platinum with 13% rhodium (+) and platinum (−)) 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.

Types R and S have close values and the same cable colors; confirm the type configured in the instrument before using the table.

Type R thermocouple, reference junction at 0 °C: −50 … 360 °C
°C	mV
−50	−0.226
−40	−0.188
−30	−0.145
−20	−0.100
−10	−0.051
0	0.000
10	0.054
20	0.111
30	0.171
40	0.232
50	0.296
60	0.363
70	0.431
80	0.501
90	0.573
100	0.647
110	0.723
120	0.800
130	0.879
140	0.959
150	1.041
160	1.124
170	1.208
180	1.294
190	1.381
200	1.469
210	1.558
220	1.648
230	1.739
240	1.831
250	1.923
260	2.017
270	2.112
280	2.207
290	2.304
300	2.401
310	2.498
320	2.597
330	2.696
340	2.796
350	2.896
360	2.997

Type R thermocouple, reference junction at 0 °C: 370 … 780 °C
°C	mV
370	3.099
380	3.201
390	3.304
400	3.408
410	3.512
420	3.616
430	3.721
440	3.827
450	3.933
460	4.040
470	4.147
480	4.255
490	4.363
500	4.471
510	4.580
520	4.690
530	4.800
540	4.910
550	5.021
560	5.133
570	5.245
580	5.357
590	5.470
600	5.583
610	5.697
620	5.812
630	5.926
640	6.041
650	6.157
660	6.273
670	6.390
680	6.507
690	6.625
700	6.743
710	6.861
720	6.980
730	7.100
740	7.220
750	7.340
760	7.461
770	7.583
780	7.705

Type R thermocouple, reference junction at 0 °C: 790 … 1200 °C
°C	mV
790	7.827
800	7.950
810	8.073
820	8.197
830	8.321
840	8.446
850	8.571
860	8.697
870	8.823
880	8.950
890	9.077
900	9.205
910	9.333
920	9.461
930	9.590
940	9.720
950	9.850
960	9.980
970	10.111
980	10.242
990	10.374
1000	10.506
1010	10.638
1020	10.771
1030	10.905
1040	11.039
1050	11.173
1060	11.307
1070	11.442
1080	11.578
1090	11.714
1100	11.850
1110	11.986
1120	12.123
1130	12.260
1140	12.397
1150	12.535
1160	12.673
1170	12.812
1180	12.950
1190	13.089
1200	13.228

Type R thermocouple, reference junction at 0 °C: 1210 … 1620 °C
°C	mV
1210	13.367
1220	13.507
1230	13.646
1240	13.786
1250	13.926
1260	14.066
1270	14.207
1280	14.347
1290	14.488
1300	14.629
1310	14.770
1320	14.911
1330	15.052
1340	15.193
1350	15.334
1360	15.475
1370	15.616
1380	15.758
1390	15.899
1400	16.040
1410	16.181
1420	16.323
1430	16.464
1440	16.605
1450	16.746
1460	16.887
1470	17.028
1480	17.169
1490	17.310
1500	17.451
1510	17.591
1520	17.732
1530	17.872
1540	18.012
1550	18.152
1560	18.292
1570	18.431
1580	18.571
1590	18.710
1600	18.849
1610	18.988
1620	19.126

Type R thermocouple, reference junction at 0 °C: 1630 … 1768.1 °C
°C	mV
1630	19.264
1640	19.402
1650	19.540
1660	19.677
1670	19.814
1680	19.951
1690	20.087
1700	20.222
1710	20.356
1720	20.488
1730	20.620
1740	20.749
1750	20.877
1760	21.003
1768.1	21.103

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