A voltage divider is one of the most common circuits in electronics: two resistors in series drop a supply voltage down to a smaller output voltage taken across the lower resistor. This calculator uses the standard formula where the output equals the input voltage multiplied by the second resistor divided by the sum of both resistors. Enter the input voltage and the two resistances and it returns the output voltage, along with the current flowing through the chain and the power dissipated. Dividers are used to scale sensor signals into an ADC range, to bias transistors and to set reference voltages. The math is quick but easy to get backward, so a dedicated tool helps you pick resistor values with confidence. Everything computes live in your browser as you type.
Output voltage equals input voltage times R2 divided by the sum of R1 and R2, written Vout equals Vin times R2 over (R1 plus R2).
R2 is the resistor across which the output is measured, connected between the output node and ground.
The formula assumes no load draws current from the output. A real load in parallel with R2 lowers the output voltage.
A voltage divider is one of the most common circuits in electronics: two resistors in series drop a supply voltage down to a smaller output voltage taken across the lower resistor. This calculator uses the standard formula where the output equals the input voltage multiplied by the second resistor divided by the sum of both resistors.
Yes. Voltage Divider Calculator is completely free, with no sign-up and no usage limits.
Yes. Voltage Divider Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Voltage Divider Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.