Voltage Divider Calculator

Compute output voltage, current, and resistor ratio.

Vin R1 Vout R2 Vout = Vin · R2/(R1+R2)

Values

Result

Vout = 2.50 V · divider current 250 µA · ratio R2/(R1+R2) = 0.5

How a voltage divider works

A resistive divider scales the input voltage: Vout = Vin · R2 / (R1 + R2). Pick large resistor values for low quiescent current, but not so large that any load on the output pulls the voltage down — the divider acts like a source with output impedance R1∥R2.

Common use: scaling a sensor or battery voltage down to an ADC input range.