PT100/PT1000
Convert RTD resistance to temperature. Enter circuit values to calculate the selected electrical quantity.
RTD Parameters
Electronics guide · Circuit components and networks
About PT100 and PT1000 Calculator
Estimate temperature from measured resistance for a PT100 or PT1000 resistance temperature detector. The calculator selects the nominal resistance at 0°C and applies a linear platinum temperature approximation, reporting Celsius, Fahrenheit, and Kelvin.
Component calculations simplify a circuit into a formula or ideal model. Real parts have tolerances, ratings, parasitic effects, and wiring details that can change how a circuit behaves, so use the result as a design estimate and compare it with the component datasheet and circuit conditions.
How to Use This Tool
- 1.Choose PT100 or PT1000 to set the nominal resistance at 0°C.
- 2.Enter the measured resistance in ohms.
- 3.Calculate and compare the estimate with the sensor datasheet and measurement circuit conditions.
Technical Details to Check
1.Match values to the right circuit position
Resistors, capacitors, inductors, and semiconductor pins are not interchangeable inputs. Follow the labels or diagram and check that each value belongs to the correct component or branch.
2.Ideal formulas have assumptions
A calculator may assume a balanced bridge, an ideal switch, a simple RC or RL network, or a specific transistor operating mode. Confirm that the real circuit matches that model before using the result.
3.Datasheet ratings still matter
Calculated values do not establish a safe operating point. Check voltage, current, power, temperature, frequency, and tolerance ratings for every part that will be used.
4.Small errors can move the result
Component tolerances and measurement uncertainty can change timing, bias, resonance, or dissipation. For a design with tight limits, calculate a range using realistic minimum and maximum values.
How the Calculation Works
The current page uses a linear approximation with platinum coefficient α = 0.00385. It relates resistance change from the nominal 0°C resistance to temperature. A PT100 is nominally 100 Ω at 0°C, while PT1000 is 1,000 Ω. The tool converts the estimate to other temperature scales.
Worked Example
Near 0°C, a PT100's resistance rises by about 0.385 Ω per degree under the nominal alpha approximation.
Where This Tool Can Help
Interpret a basic RTD resistance reading or compare the nominal scale of PT100 and PT1000 sensors.
Checking a first design estimate
Use the formula result to choose a likely component range, then test the circuit with real part values and operating conditions.
Learning how a circuit behaves
Change one input at a time and observe the result to see how a resistor, capacitor, inductor, or device parameter affects the calculation.
Comparing candidate components
Compare values on the same unit basis, then check package, tolerance, power rating, voltage rating, and availability in the relevant datasheet.
Reviewing a schematic
Use the result as a cross-check for a hand calculation, simulation, or design note while keeping the assumed topology clear.
Tips for More Reliable Results
- Use consistent units and copy component values carefully, including prefixes such as m, µ, n, and k.
- Check polarity, pin names, and series or parallel placement against the circuit diagram.
- Use worst-case component tolerances when a timing or operating range must stay within limits.
- Verify the result against datasheets and an appropriate bench measurement before building a safety-critical circuit.
Limitations and Assumptions
The linear formula is approximate and less accurate across a wide temperature range than the IEC platinum RTD equation. Lead resistance, wiring method, self-heating, sensor tolerance, and calibration matter. Use the sensor datasheet and a proper measurement circuit for precision or safety work.
The calculator can only model the values, topology, and operating assumptions represented by its inputs. It does not inspect a physical circuit, validate wiring, or confirm a part is safe for its electrical and thermal conditions. Use design documentation and datasheets for final component choices.
Frequently Asked Questions
What does PT100 mean?
It is a platinum RTD with nominal resistance of 100 Ω at 0°C.
What does PT1000 mean?
Its nominal resistance is 1,000 Ω at 0°C.
Is the result a full RTD calibration?
No. It uses a simple linear approximation rather than a full calibration curve.
Will the result exactly match a real circuit?
Not always. The formula may use ideal components and may not include tolerances, parasitic effects, loading, or temperature changes.
Can I select a component from the calculated value alone?
No. Also check ratings, tolerance, package, polarity, availability, and the circuit's operating conditions.