Voltage Divider Calculator

How to design a voltage divider

1. Choose whether to find the output voltage or the R2 value for a target output.
2. Enter the input voltage and R1.
3. Enter R2 or the target output voltage.

Frequently asked questions

What is the formula?

Vout = Vin × R2 / (R1 + R2). It holds when the load connected to the output draws much less current than the divider itself.

Can I use a voltage divider as a power supply?

Not for loads that draw much current, because the output drops as the load draws more. Use a voltage regulator instead.

How do I get half the input voltage?

Make R1 and R2 the same value.