Free workshop tool
Voltage Divider Calculator
Calculate output voltage, divider current and resistor dissipation for a simple two-resistor unloaded voltage divider.
Unloaded divider. This assumes nothing significant is connected to the output. A real load changes the effective value of R2 and therefore the output voltage.
Formula
Voltage divider equations
Output voltage
Vout = Vin × R2 ÷ (R1 + R2).
Divider current
Current through an unloaded divider = Vin ÷ (R1 + R2). Individual resistor dissipation is I²R.
Related free tools
Ohm’s Law & Power Calculator · Resistors Series & Parallel Calculator