About the Voltage Divider Calculator
Output voltage of a two-resistor divider, the current it draws, and R2 for a target output.
Also known as: potential divider, resistor divider, vout calculator, divide voltage.
How to use this calculator
- Enter calculate, input voltage, r1 (top) and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
V_out = V_in × R₂ / (R₁ + R₂)
Worked example
Using the values pre-filled in the calculator above:
- Calculate: Output voltage
- Input voltage = 12 V
- R1 (top) = 10,000 Ω
- R2 (bottom) = 4,700 Ω
the calculator returns:
- Output voltage: 3.8367 V
- Divider current: 0.8163 mA
- Power in R1: 6.664 mW
- Power in R2: 3.132 mW
Tips & common mistakes
- A divider only holds its output if the load draws far less current than the divider itself.