Enter Values
Formula
Vout = Vin × R2 ÷ (R1 + R2)
Divider current = Vin ÷ (R1 + R2)
This formula assumes no load is connected to the output.
Example
With 12 V, R1 = 1,000 ohms, and R2 = 2,000 ohms, the unloaded output is 8.00 V.
Divider Orientation
R1 connects from the input supply to the output node. R2 connects from the output node to ground or the supply return. Reversing R1 and R2 changes the output voltage.
The divider current shown is the current through both resistors when no external load is connected.
Loading and Component Ratings
A connected load appears in parallel with R2 and normally lowers the output voltage. For accurate results, the load impedance should be much higher than R2 or should be included in an equivalent-resistance calculation.
Check resistor tolerance, power dissipation, source impedance, and the receiving circuit's input current before building the divider.