Online Tool Store
Simple Circuit Voltage Divider Calculator
Enter a source voltage and two resistor values to calculate the output voltage of a simple voltage divider circuit. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Example
Simple Circuit Voltage Divider Calculator
Sample: 9V source, R1=1kΩ, R2=2kΩ
Example shown — replace it with your own resistor values.
Source
9V
R1
1 kΩ
R2
2 kΩ
Result
How it works
- Enter your source voltage.
- Enter the two resistor values, R1 and R2.
- Get the output voltage across R2.
The method
The standard voltage divider formula calculates output voltage as a fraction of input voltage, based on the ratio between the two resistors.
FAQ
What formula does this use?
The voltage divider formula, Vout = Vin × (R2 / (R1 + R2)), calculating the voltage across the second resistor in a series pair.
What is a voltage divider used for?
Common uses include scaling down a voltage for a sensor or microcontroller input, or creating a reference voltage from a single supply.
Does this account for load current draw?
No — this assumes an ideal, unloaded divider; a load connected across the output will pull the actual voltage lower than this calculation shows.
How we compare
| Feature | Online Tool Store | Manual formula calculation | Circuit simulation software |
|---|---|---|---|
| No software install | Yes | Yes | No |
| Quick to start | Yes | Slow | Setup required |
| Free to use | Yes | Free | Often paid |
For a quick check without opening simulation software, this gets you the output voltage instantly.