Voltage Divider Calculator
Find the unloaded DC output across the lower resistor R2 of a two-resistor divider.
Formula
Vout = Vin × R₂/(R₁ + R₂).
Input voltage: 12 V · Upper resistor R1: 1,000 Ω · Lower resistor R2: 2,000 Ω · Output voltage ≈ (12 V)×(2,000 Ω)÷((1,000 Ω)+(2,000 Ω))
How to use
- Enter the DC supply voltage.
- Enter R1 from supply to output and R2 from output to ground.
- Read the voltage across R2.
Examples
- 12 V, R1 = 1 kΩ and R2 = 2 kΩ give 8 V.
Frequently asked questions
Which resistor is R2?
The lower resistor connected between the output node and ground.
What if I connect a load?
This unloaded result changes. Use the parallel equivalent of R2 and a resistive load.
Are tolerances included?
No. Values are ideal; actual resistance and loading affect output.
Sources
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