Voltage Divider Calculator with 4 Resistors

This tool calculates the voltage across each of four (4) resistors in series.

Enter the Input Voltage Vin, and resistor values R1, R2, R3 and R4. Use the drop down menu to select the units.

Formula

V1=Vin*R1/(R1+R2+R3+R4)

V2=Vin*R2/(R1+R2+R3+R4)

V3=Vin*R3/(R1+R2+R3+R4)

V4=Vin*R4/(R1+R2+R3+R4)

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

If you want to calculate the voltage drop across two resistors in series, set R3=0 and R4=0. In the equations above V3 and V4 will be zero (no voltage drop across a short circuit) and effectively this is reduced to a two resistor divider network.

The series resistors have the same current flowing through them. What about resistors that are connected in parallel?

Example Calculation

With R1=1Ω, R2=3Ω, R3=7Ω, R4=10Ω and Vin=12V, the voltages

  • V1=0.57 V
  • V2=1.71 V
  • V3=4 V
  • V4=5.71 V

The sum of the 4 voltages = the input voltage. As a check you can see that 0.57+1.71+4+5.71= 12 V

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