Voltage Divider Calculator
Enter the input voltage plus any two of Vout, R1, or R2 to solve for the missing value.
Current through divider
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How a Voltage Divider Works
A voltage divider uses two resistors in series to scale down an input voltage. The formula is Vout = Vin × R2 ÷ (R1 + R2), where R2 is the resistor connected to ground (the "bottom" resistor) and R1 is connected to the input voltage (the "top" resistor). Fill in Vin plus any two of Vout, R1, or R2, and this tool solves for whichever one you left blank.
Voltage dividers are a classic example of a series circuit. For the underlying math, see Ohm's Law Explained.