Pt100 resistance table (IEC 60751)
A Pt100 resistance table lists the resistance of a platinum RTD at each temperature according to IEC 60751: 100.00 ohm at 0 °C, rising by roughly 0.385 ohm per °C — 138.51 ohm at 100 °C and 18.52 ohm at −200 °C.
Move the pointer along the curve to read the resistance at any temperature.
Resistance table
The table gives the resistance of a Pt100 element every 10 °C from −200 °C to 850 °C, calculated from the IEC 60751 characteristic. Find the temperature, read the resistance — and interpolate between rows for values in between.
| °C | +0 | +10 | +20 | +30 | +40 | +50 | +60 | +70 | +80 | +90 |
|---|---|---|---|---|---|---|---|---|---|---|
| -200 | 18.52 | 22.83 | 27.10 | 31.34 | 35.54 | 39.72 | 43.88 | 48.00 | 52.11 | 56.19 |
| -100 | 60.26 | 64.30 | 68.33 | 72.33 | 76.33 | 80.31 | 84.27 | 88.22 | 92.16 | 96.09 |
| 0 | 100.00 | 103.90 | 107.79 | 111.67 | 115.54 | 119.40 | 123.24 | 127.08 | 130.90 | 134.71 |
| 100 | 138.51 | 142.29 | 146.07 | 149.83 | 153.58 | 157.33 | 161.05 | 164.77 | 168.48 | 172.17 |
| 200 | 175.86 | 179.53 | 183.19 | 186.84 | 190.47 | 194.10 | 197.71 | 201.31 | 204.90 | 208.48 |
| 300 | 212.05 | 215.61 | 219.15 | 222.68 | 226.21 | 229.72 | 233.21 | 236.70 | 240.18 | 243.64 |
| 400 | 247.09 | 250.53 | 253.96 | 257.38 | 260.78 | 264.18 | 267.56 | 270.93 | 274.29 | 277.64 |
| 500 | 280.98 | 284.30 | 287.62 | 290.92 | 294.21 | 297.49 | 300.75 | 304.01 | 307.25 | 310.49 |
| 600 | 313.71 | 316.92 | 320.12 | 323.30 | 326.48 | 329.64 | 332.79 | 335.93 | 339.06 | 342.18 |
| 700 | 345.28 | 348.38 | 351.46 | 354.53 | 357.59 | 360.64 | 363.67 | 366.70 | 369.71 | 372.71 |
| 800 | 375.70 | 378.68 | 381.65 | 384.60 | 387.55 | 390.48 | — | — | — | — |
Read the row for the tens of degrees and the column for the units: the row −200 and the column +90 give −110 °C.
The Callendar-Van Dusen formula
Every value in the table comes from one formula, defined in IEC 60751.
Above 0 °C: R(t) = R0 · (1 + A·t + B·t²)
Below 0 °C: R(t) = R0 · (1 + A·t + B·t² + C·(t − 100)·t³)
with R0 = 100 Ω, A = 3.9083 × 10−3 °C−1, B = −5.775 × 10−7 °C−2 and C = −4.183 × 10−12 °C−4.
Worked example
A Pt100 reads 109.73 Ω. The table places the value between 100.00 Ω (0 °C) and 138.51 Ω (100 °C); the row at 20 °C reads 107.79 Ω and the row at 30 °C reads 111.67 Ω. The formula gives the exact answer: 25.0 °C.
Pt100 calculator
Type a value in either field — the other follows the IEC 60751 curve.
The table shows the nominal curve
The table is the nominal IEC 60751 characteristic — the curve a Pt100 is built to follow. A real element deviates from it within its tolerance class: at 100 °C, a Class B element may deviate up to ±0.80 °C, which is roughly ±0.3 Ω. The classes and their formulas are covered under Pt100 tolerance classes.
Frequently asked questions
What resistance does a Pt100 have at 25 °C?
109.73 Ω according to IEC 60751. Around room temperature the sensitivity is close to 0.39 Ω per °C, so each tenth of a degree moves the reading by roughly 0.04 Ω.
Why is it called Pt100?
Pt is the chemical symbol for platinum, and 100 is the element's resistance in ohms at 0 °C — exactly 100.00 Ω. Pt500 and Pt1000 follow the same curve with 500 Ω and 1,000 Ω at 0 °C.
What is the difference between Pt100 and Pt1000?
Both follow the same IEC 60751 characteristic and the same tolerance classes — a Pt1000 simply has ten times the resistance at every temperature: 1,000 Ω at 0 °C. The higher base resistance makes lead resistance ten times less significant, which is why Pt1000 elements are usually connected with two wires.
Which formula converts Pt100 resistance to temperature?
The Callendar-Van Dusen formula — the same one behind this table. Above 0 °C it is a quadratic equation that can be solved directly for temperature; below 0 °C the table or an iterative calculation is used.
Related
- Temperature sensor types and ranges — Pt100 tolerance classes and temperature ranges
- Pt100 wiring: 2-, 3- and 4-wire — how the resistance is measured without the cable disturbing it
- Temperature transmitter guide — when the resistance leaves the head as 4–20 mA
- Temperature sensors — the Kjaerulf Pedersen a/s temperature sensor programme
- Knowledge Center — all reference guides and tools
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