PT1000 RTD Resistance Table: Full Chart -200 to 850 °C

Updated 15 October 2026: corrected the α value and the slope column, completed the table to 850 °C, and added the °F and resistance lookup tables. Reviewed by the Focusens Engineering Team.

On this page: Basics · Full table · °F table · Ω to °C lookup · Equation · Tolerance classes · Lead error · Self-heating · Construction

1. PT1000 basics: 1000.00 Ω at 0 °C

A PT1000 is a platinum RTD with a nominal resistance R0 of 1000.00 Ω at 0 °C. It follows the same normalized curve as a PT100, so every PT1000 value is exactly ten times the PT100 value at the same temperature. The same chart on the 100 Ω base is the PT100 resistance table. Because both follow the same curve and tolerance classes, the choice between them comes down to cable length and input support, which our PT100 vs PT1000 comparison covers.

A PT1000 has no single slope. 3.85 Ω/°C is the average from 0 to 100 °C, the figure α = 0.00385 describes. 3.908 Ω/°C is the tangent at 0 °C, and the tangent falls to 2.93 Ω/°C at 850 °C. To convert a small resistance error such as cable resistance into degrees, divide by the tangent at the working temperature.

2. Complete PT1000 resistance table, -200 to 850 °C

Values come from the Callendar-Van Dusen equation in section 5, rounded to 0.01 Ω. The row gives the tens and the column gives the units: row 120, column 6 is 126 °C, which reads 1483.28 Ω. In the negative table the columns count down: row -120, column -6 is -126 °C, which reads 496.49 Ω.

Negative range: -200 to -1 °C

Positive range: 0 to 850 °C

3. PT1000 table in °F

Each row is a 50 °F step and each column adds 0, 10, 20, 30 or 40 °F: row 200, column +20 is 220 °F. The table runs from -320 to 1560 °F, and the curve itself ends at -328 °F (-200 °C) and 1562 °F (850 °C). For a value between columns, convert with (°F - 32) × 5/9 and read the °C table.

4. Meter reading to temperature: PT1000 lookup

A multimeter on a PT1000 gives ohms, and the question is usually what temperature that means. The table below goes the other way, from round resistance values to temperature. Between rows, divide the difference by the local slope from section 1.

A reading near 1097 Ω is a healthy PT1000 at room temperature (25 °C). A reading of a few ohms means a short, an open circuit shows OL (over range) on the meter, and a reading near 110 Ω means the part is a PT100, not a PT1000.

5. The Callendar-Van Dusen equation behind the table

For 0 to 850 °C: R(t) = R0 × (1 + A·t + B·t²)

For -200 to 0 °C: R(t) = R0 × [1 + A·t + B·t² + C·(t - 100)·t³]

IEC curve vs the old JPt100 curve

Everything on this page assumes α = 0.00385 (written 3.851 × 10⁻³ °C⁻¹ in IEC 60751:2022), the curve in IEC 60751 and ASTM E1137. Older Japanese JPt100 elements (JIS C 1604-1981, α = 0.003916) follow a steeper curve. Read a JPt100 through an α = 0.00385 table and it reads high: by our calculation about 1.7 °C at 100 °C, 3.5 °C at 200 °C and 5.3 °C at 300 °C. JIS C 1604:2013, based on IEC 60751:2008, uses the IEC curve, so a JPt100 now turns up mainly in old instruments and old spare parts.

6. IEC 60751 tolerance classes for a PT1000

Each class allows a deviation that grows with temperature. IEC 60751:2022 sets the range of validity separately for probes built with wire-wound and with film elements, so a probe with a film element cannot be sold as class A at 400 °C even though the formula gives a number there. The ranges below are for complete thermometers (Table 2 of the standard). Bare elements are graded separately as W 0.1 to W 0.6 and F 0.1 to F 0.6 (Table 1), and two wire-wound ranges differ there: W 0.1 covers -100 to 350 °C, and W 0.3 and W 0.6 reach 660 °C.

A tolerance class covers the element as delivered. It does not cover drift in service, the instrument input or the cable. A class A element wired 2-wire on a long run can still read several degrees off, and IEC 60751:2022 (clause 5.5) requires 3-wire or 4-wire connection for any thermometer better than class B.

7. Lead resistance: what a 2-wire cable adds to a PT100 and a PT1000

In a 2-wire circuit the instrument measures the element plus both leads. The error in degrees is the loop resistance divided by the local slope. With 24 AWG copper at 0.0842 Ω per metre (20 °C):

A 3-wire input cancels most of the lead resistance when the leads match, and a 4-wire input removes it. How to wire each one is in PT100 and PT1000 3-wire wiring and color codes, and the arithmetic for unbalanced leads is in RTD lead resistance error.

8. Self-heating and excitation current

The measuring current heats the element. The rise above the medium is ΔT = I²·R / δ, where δ is the dissipation constant in mW/°C from the element or probe datasheet. At 1 mA a PT1000 dissipates 1 mW, at 0.1 mA only 0.01 mW.

The δ values are typical figures chosen to show the scale. Use the dissipation constant from your own element or probe datasheet; some datasheets give the inverse, a self-heating coefficient in °C/mW. IEC 60751:2022 (clause 5.3) limits the measuring current so that self-heating under its test conditions stays below 25 % of the class tolerance. In still air the rise at 1 mA is already larger than the whole class AA tolerance at 0 °C, which is one reason PT1000 inputs run at low current.

9. Thin-film vs wire-wound PT1000 elements

Focusens PT1000 probes

Focusens builds PT1000 and PT100 probes to IEC 60751 class A or B, in 2-, 3- and 4-wire versions, for HVAC, beverage machines and industrial equipment. Order a class A probe as 3-wire or 4-wire:

• Factory customized PT100 and PT1000 temperature sensors
• Class A PT1000 3-wire probe
• PT100 and PT1000 probes for coffee machines
• All RTD sensors

What the standard fixes beyond the table is in the resistance temperature detector guide. For a custom probe, send us the range, class, wiring and cable length.