Voltage Divider Calculator
Find the output voltage of a two-resistor divider from the input voltage and resistor values.
Output voltage6.000V
Current through divider60.000mA
A voltage divider taps the junction of two series resistors. Vout = Vin × R2 ÷ (R1 + R2), measured across R2 (the bottom resistor). With 12 V in and R1 = R2 = 100 Ω, Vout = 12 × 100 ÷ 200 = 6 V. The current through the chain is Vin ÷ (R1 + R2) — here 12 ÷ 200 = 0.06 A = 60 mA. Note this unloaded output sags if the tap drives a real load.
Questions
What is the voltage divider formula?
Vout = Vin × R2 ÷ (R1 + R2), where R2 is the resistor you measure across. With 12 V and two equal 100 Ω resistors, Vout = 12 × 100 ÷ 200 = 6 V.
Does a load change the output?
Yes. The formula gives the unloaded output. Connecting a load in parallel with R2 lowers the effective R2 and drops the output, so keep the divider's current well above the load's.