This tool calculates the voltage across each of three (3) resistors in series.

Enter the Input Voltage **Vin**, and resistor values **R1**, **R2**, and **R3**.

**Formula**

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

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

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

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**. In the equations above **V3** will be zero (no voltage drop across a short circuit) and effectively this is reduced to a two resistor divider network.

**Example Calculation**

With R1=1Ω, R2=3Ω, R3=5Ω and Vin=12V, the voltages

- V1 = 1.33V
- V2 = 4V
- V3 = 6.67V

The sum of the 3 voltages = the input voltage. As a check you can see that 1.33+4+6.67 = 12V

**Related Calculators**

- Voltage Divider Calculator with 2 resistors
- Voltage Divider Calculator with 4 resistors
- Voltage Divider Calculator with 5 resistors