Voltage Divider Calculator
Calculate output voltage of a resistor voltage divider.
About this tool
A voltage divider uses two resistors in series to produce a lower output voltage from a higher input voltage. This calculates the output voltage measured across R2, using Vout = Vin \u00d7 R2 / (R1 + R2).
Key Features
- Standard two-resistor voltage divider formula
- Also shows current through the divider
- Instant validation on invalid resistor values
How to Use
- Enter the input voltage.
- Enter R1 (the resistor closest to the input) and R2 (the resistor the output is measured across).
- Click Calculate Vout.
Benefits
- Design a voltage divider for sensor or logic-level conversion
- Check circuit calculations before building
- Understand how resistor ratios set the output voltage
Frequently Asked Questions
R1 is the resistor between the input voltage and the output node; R2 is the resistor between the output node and ground — the output voltage is measured across R2.
No — this assumes the output isn't loaded (or the load's resistance is very high compared to R2). Connecting a low-resistance load will pull the actual output voltage down from this ideal calculation.