RTD resistance ↔ temperature
Convert between temperature and resistance for platinum RTDs with the Callendar–Van Dusen equation. Default Pt385 coefficients, or enter your sensor’s own A, B and C from its calibration certificate.
RTD · Callendar–Van Dusen
v0.1.0 · Pt385Calculated resistance138.5055 ΩdR/dt = 0.37928 Ω/°C
R(t) = R₀[1 + At + Bt² + C(t − 100)t³] · C = 0 for t ≥ 0 °C · valid −200 to 850 °C
Test vectors for this tool
The reference cases this calculator is tested against on every change. Use them to check your own software. All test vectors · Download JSON
| ID | Inputs | Expected | Tolerance | Source |
|---|---|---|---|---|
| RTD-F-01 | t_C = -200, r0 = 100 | 18.52 Ω | ± 0.005 | CvD Pt385; cross-check IEC 60751 table |
| RTD-F-02 | t_C = -100, r0 = 100 | 60.26 Ω | ± 0.005 | CvD Pt385; cross-check IEC 60751 table |
| RTD-F-03 | t_C = 0, r0 = 100 | 100 Ω | ± 0.00005 | Definition of R0 |
| RTD-F-04 | t_C = 100, r0 = 100 | 138.5055 Ω | ± 0.00005 | CvD Pt385, exact arithmetic: 100(1 + 0.39083 − 0.005775) |
| RTD-F-05 | t_C = 200, r0 = 100 | 175.86 Ω | ± 0.005 | CvD Pt385; cross-check IEC 60751 table |
| RTD-F-06 | t_C = 500, r0 = 100 | 280.98 Ω | ± 0.005 | CvD Pt385; cross-check IEC 60751 table |
| RTD-F-07 | t_C = 850, r0 = 100 | 390.48 Ω | ± 0.005 | CvD Pt385; cross-check IEC 60751 table |
| RTD-F-08 | t_C = 100, r0 = 1000 | 1385.055 Ω | ± 0.0005 | CvD Pt385 scaled to R0 = 1000 Ω (Pt1000) |
| RTD-I-01 | r_ohm = 138.5055, r0 = 100 | 100 °C | ± 0.0001 | Inverse of RTD-F-04 |
| RTD-I-02 | r_ohm = 60.2558, r0 = 100 | -100 °C | ± 0.001 | Inverse of CvD Pt385 at −100 °C (60.2558 Ω) |
| RTD-I-03 | r_ohm = 100, r0 = 100 | 0 °C | ± 0.0001 | Definition of R0 |
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