Voltage Divider Calculator

R1 = ? Ω
R2 = ? Ω
Vout

R1 is the top resistor (from Vin), R2 is the bottom one (to GND)

Voltage Divider Calculator

A voltage divider circuit is a circuit that takes a higher voltage and converts it into a lower one by using a pair of resistors connected in series.

The formula for calculating the output voltage is based on Ohm’s Law and is shown below.

Voltage Divider Formula

Vout = Vs × R2 / (R1 + R2)

Where:

  • Vs — Source voltage, measured in volts (V)
  • R1 — Resistance of the 1st resistor (Ω)
  • R2 — Resistance of the 2nd resistor (Ω)
  • Vout — Output voltage, measured in volts (V)

Enter any three known values and press Calculate to solve for the other. Voltage divider circuits are commonly used in robotics, signal conditioning, and microcontroller platforms like Arduino and ESP32.

Voltage Divider Circuit Diagram