Thermistor Resistance vs Temperature

Convert thermistor resistance ↔ temperature using the Beta model (fast) or optional Steinhart–Hart (3-point fit).

How to Use

  1. Pick your model: Beta (most common) or Steinhart–Hart (3 calibration points).
  2. Enter your thermistor parameters (R0, T0, Beta) or 3-point data.
  3. Enter either resistance or temperature to solve the other.
  4. Optional: generate a table across a temperature range for quick lookup.
Thermistor Lab
Live conversion + table preview. Work shown in Kelvin where applicable.
Model
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T
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R
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Slope
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Type: —
Temp → R Preview (not to scale)
Inputs & Settings
Use Beta model for most NTC datasheets. Steinhart–Hart is optional (3 points).
Common: 0°C, 25°C, 85°C. Use K if your datasheet specifies Kelvin.
Enter the measured thermistor resistance (or target resistance).
Typical NTCs: 10kΩ @ 25°C, 100kΩ @ 25°C.
Usually 25°C unless your datasheet says otherwise.
Common values: 3435, 3950, 4200 (K).
Enter 3 temperature/resistance pairs from datasheet.
Example only. Use your datasheet values.
Midpoint is often 25°C.
This is often R₀ at T₀.
Use a hot-side datasheet point.
Example only. Use your datasheet values.
Table Output (temperature sweep)
Temp Resistance
Set Tmin/Tmax/Step and choose “Table” to generate rows.
Table calculations use the selected model and parameters. Temperature is converted to Kelvin internally.
Show Work (step-by-step)
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Work is shown using base units (K and Ω) for clarity. Conversions to °C/°F/kΩ are shown as needed.

Reference

Beta model (common NTC datasheets)

Convert temperature to resistance: R(T) = R₀ · exp( β · (1/T − 1/T₀) )

Convert resistance to temperature: 1/T = 1/T₀ + (1/β) · ln(R/R₀)

T and T₀ are in Kelvin. β is in Kelvin. R and R₀ are in ohms.

Steinhart–Hart (3-point)

1/T = A + B·ln(R) + C·(ln(R))³ (T in Kelvin, R in ohms).

This tool can fit A/B/C from three (T,R) points (client-side) for improved accuracy over wider ranges.

FAQ

What’s the difference between NTC and PTC?

NTC thermistors decrease in resistance as temperature rises. PTC devices increase in resistance as temperature rises.

Why do I need Kelvin?

The Beta and Steinhart–Hart equations are defined in absolute temperature. The tool converts °C/°F to Kelvin automatically.

Is the Beta model accurate?

It’s usually very good near the reference temperature (often 25°C). Steinhart–Hart can be more accurate across a larger span if you have 3 points.

My datasheet gives “β25/85” — what is that?

It’s a Beta value derived between two temperatures (25°C and 85°C). Use it as β in the Beta model, keeping in mind it’s an approximation across the full range.

Tool Info

Last updated:

Updates may include model accuracy improvements, table/export enhancements, and edge-case handling.