Voltage Divider Calculator
Work out the output voltage of a two-resistor voltage divider.
Splitting a voltage down
A voltage divider uses two resistors to produce a fraction of an input voltage — a simple, common way to get a lower voltage from a higher one, or to read a variable resistance as a voltage. This works out the output from the input and the two resistor values, a building block that appears constantly in electronics.
Enter the input voltage and the two resistors to see the output.
Where dividers work and where they don't
Voltage dividers are perfect for low-current jobs — setting a reference voltage, reading a sensor, feeding a high-impedance input. Their limitation, worth understanding, is that they are not a good way to power anything that draws real current, because drawing current changes the output voltage and wastes energy as heat in the resistors. For supplying power you want a proper regulator, not a divider.
Frequently asked questions
What is a voltage divider good for?
Producing a reference voltage, reading a sensor, or feeding a high-impedance input — low-current sensing and reference jobs.
Can I use it to power a device?
No — drawing real current changes the output and wastes energy as heat. For supplying power, use a proper voltage regulator.
Is anything uploaded?
No. The calculation happens in your browser.