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Voltage Divider Calculator

Calculate output voltage or resistor values

Result

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Formula

VoutVout = Vin × R2 ÷ (R1+R2)

Circuit Diagram

    Vin ──┬── R1 ──┬── GND
          │        │
          │       Vout
          │        │
          └── R2 ──┘

Understanding Voltage Dividers

A voltage divider is a simple circuit that reduces voltage using two resistors in series. The output voltage is a fraction of the input voltage determined by the resistor ratio.

Applications

Voltage dividers are used for level shifting (e.g., 5V to 3.3V for microcontrollers), creating reference voltages, reading sensors, and in audio volume controls (potentiometers).

Limitations

Voltage dividers are not efficient for power delivery - they waste energy as heat. For significant current loads, use a voltage regulator instead.

Frequently Asked Questions

For low power applications, use 1kΩ-100kΩ. Lower values draw more current; higher values may cause noise issues. The ratio matters more than absolute values.

Generally no. Voltage dividers have poor load regulation - the output voltage drops significantly when current is drawn. Use a voltage regulator for powering devices.