Voltage Divider Calculator

This tool calculates the voltage drop across each resistor in a series network of two resistors.

Enter

  • Input Voltage Vin
  • R1 and R2 in milliOhm/Ohm/kiloOhm/megaOhm

Formula

V1=Vin*R1/(R1+R2)

V2=Vin*R2/(R1+R2)

The largest voltage drop will be across the larger resistor value. Conversely, the smallest voltage drop will be across the smaller.

If you want to calculate the voltage drop across a single resistor set R2=0 and from the equations above, V1=Vin and V2=0 (which makes sense).

Example Calculation

With R1=1Ω, R2=3Ω, Vin=12V, the voltages

  • V1=3V
  • V2=9V

The sum of the two voltages = the input voltage. As a check you can see that 3+9= 12V

Related Calculators

Voltage Divider Calculator with 3 resistors

Voltage Divider Calculator with 5 resistors