Potentiometer Calculator

A potentiometer is a variable resistor that divides an input voltage into a lower output voltage — used in everything from audio volume knobs to sensor circuits. Enter your Input Voltage, Total Potentiometer Resistance, and Wiper Position into the Potentiometer Calculator to get the Output Voltage at the wiper. Secondary outputs include Voltage Ratio, Upper Resistance, and Lower Resistance — with optional loaded-circuit results if you add a Load Resistance.

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Leave blank for unloaded calculation

Results

Output Voltage

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Voltage Ratio

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Upper Resistance

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Lower Resistance

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Frequently Asked Questions

What is a potentiometer and how does it work?

A potentiometer is a three-terminal resistor with a sliding or rotating contact (wiper) that forms an adjustable voltage divider. By moving the wiper, you can vary the output voltage between 0V and the input voltage.

How do I calculate potentiometer output voltage?

The output voltage equals the input voltage multiplied by the ratio of lower resistance to total resistance: Vout = Vin × (R_lower / R_total). The wiper position determines this resistance ratio.

What happens when I connect a load to the potentiometer?

Adding a load resistance in parallel with the lower portion of the potentiometer reduces the effective resistance, which changes the output voltage. The loaded output will be lower than the unloaded calculation.

Why is my potentiometer output voltage different than calculated?

Real-world factors include potentiometer tolerance (typically ±20%), temperature effects, and loading effects from connected circuits. Buffer the output with a high-impedance amplifier for more stable voltage.

Can I use a potentiometer as a voltage regulator?

No, potentiometers are not suitable as voltage regulators because they cannot maintain constant voltage under varying load conditions. Use proper voltage regulator circuits for stable output voltage.

What's the difference between linear and logarithmic potentiometers?

Linear potentiometers have resistance that changes proportionally with position, while logarithmic (audio taper) potentiometers have non-linear resistance change. This calculator assumes linear potentiometers.

How do I choose the right potentiometer resistance value?

Consider your input voltage, desired current draw, and load requirements. Higher resistance values draw less current but are more susceptible to noise. Common values range from 1kΩ to 1MΩ.

What is wiper resistance and should I account for it?

Wiper resistance is the contact resistance between the wiper and resistive element, typically 1-100 ohms. For precision applications with low-value potentiometers, this can affect accuracy and should be considered.