Voltage Divider Calculator

Enter value and click on calculate. Result will be displayed.
Vin
Volts
Ra
Ohms
Rb
Ohms
Result:
Vout:
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What is a Voltage Divider Calculator?
A Voltage Divider Calculator is a tool (digital, online, or in software) that helps you quickly figure out the output voltage of a voltage divider circuit. A voltage divider is a basic electrical circuit made up of two resistors in series that splits the input voltage into a smaller, controlled voltage.

Why use a Voltage Divider Calculator?

  • Saves time: It automates the math so you don’t have to calculate manually.
  • Reduces errors: It ensures the voltage division calculation is accurate.
  • Design help: It helps you choose the right resistor values to get a specific output voltage.
  • Useful for prototyping: You can quickly tweak and test different resistor combinations without doing repeated calculations.

How does a Voltage Divider Calculator work?
The calculator uses this formula:

 

Where:

  • Vin = Input voltage
  • R1 = First resistor
  • R2 = Second resistor
  • Vout = Output voltage

You just enter Vin, R1, and R2, and the calculator gives you Vout . Some calculators also work in reverse — you can enter your desired Vout and it will help you figure out the right resistor values.

When do you use a Voltage Divider Calculator?

  • Stepping down voltage: When you need a lower voltage for sensors or microcontroller inputs.
  • Analog signal control: To scale down analog voltage levels for compatibility with ADCs (analog-to-digital converters).
  • Biasing components: Like setting reference voltages for transistors or op-amps.
  • Testing and prototyping: Quickly adjusting voltage levels while building circuits.