RTD Calculator

An RTD (Resistance Temperature Detector) is a sensor that measures temperature by changing its electrical resistance — and this calculator converts between the two. Select your calculation mode, RTD type (PT100, PT500, or PT1000), and coefficient standard, then enter either an RTD resistance (Ω) or a temperature to get the corresponding converted value, plus thermometer sensitivity and nominal resistance at 0°C.

Calculation Mode *

Ω

Measured resistance value from RTD sensor

°C

Temperature value to convert to resistance

Results

Calculated Result

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Thermometer Sensitivity (dR/dT)

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Nominal Resistance at 0°C

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Frequently Asked Questions

Why convert resistance to temperature in RTD sensors?

RTD sensors measure temperature by detecting changes in electrical resistance. Converting resistance to temperature provides the actual temperature reading needed for process control, monitoring, and safety applications in industrial settings.

What is the difference between PT100, PT500, and PT1000 RTDs?

The numbers indicate the nominal resistance at 0°C: PT100 has 100Ω, PT500 has 500Ω, and PT1000 has 1000Ω. Higher resistance RTDs provide better sensitivity and accuracy but may be more susceptible to lead wire resistance errors.

What does the coefficient α = 0.00385 mean?

The temperature coefficient α represents how much the resistance changes per degree of temperature change. α = 0.00385 is the IEC 751 standard for platinum RTDs, meaning resistance increases by 0.385% per °C.

How accurate are RTD temperature calculations?

RTD calculations using standard coefficients are highly accurate, typically within ±0.1°C for industrial applications. Accuracy depends on the RTD quality, calibration, measurement electronics, and proper installation.

What is thermometer sensitivity (dR/dT)?

Thermometer sensitivity represents the rate of resistance change per degree of temperature change at a specific temperature. It's measured in ohms per degree (Ω/°C) and indicates how responsive the RTD is to temperature changes.

Can I use this calculator for custom RTD types?

This calculator is designed for standard platinum RTDs (PT100, PT500, PT1000) with common coefficient values. For custom RTDs or non-standard materials, you would need the specific coefficients for your sensor.

What temperature range can RTDs measure?

Platinum RTDs can typically measure from -200°C to +850°C, though the exact range depends on the construction and application. This calculator supports the full industrial temperature range for standard RTDs.