Voltage Divider with Equal Resistors — Half the Input
When R1 and R2 are equal, the output of a voltage divider is exactly half the input voltage.
How to use this tool
- Enter input voltage (vin), r1 (top resistor) and r2 (bottom resistor) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your output voltage (vout) and the full breakdown beneath it.
Equal resistors in a voltage divider always produce an output that is exactly half the input voltage.
Frequently asked questions
- Why does the output voltage change when I connect a load?
- A load in parallel with R2 reduces the effective resistance, dropping Vout. For accurate division, the load resistance should be much larger than R2 (≥10×).
- How do I choose R1 and R2 for a target Vout?
- Rearrange: R1/R2 = (Vin − Vout)/Vout. Pick a convenient R2, then calculate R1.