Voltage Divider
Calculator
Results
- Output voltage (V)
- 3.836734
- Divider current (mA)
- 0.816326
- Divider ratio
- 0.319727
Electrical results
| Output voltage (V) | 3.836734 |
| Divider current (mA) | 0.816326 |
| Divider ratio | 0.319727 |
formula-map diagram
- Output voltage (V)
- 3.836734
- Divider current (mA)
- 0.816326
- Divider ratio
- 0.319727
Electrical relationship
Formula
Vout = Vin × R2 / (R1 + R2)= 3.8367346938776
Note
This is a simplified model: it applies the textbook relationship to the numbers you entered and assumes ideal components, steady-state sinusoidal conditions, balanced loads and copper resistivity of 0.0172 Ω·mm²/m at 20 °C. It ignores component tolerances, temperature drift, skin effect, harmonics, inrush, transformer and battery losses, and it is not a substitute for the wiring code that applies where you are. Have any installation sized and verified by a licensed electrician or engineer.
More in Electrical engineering
See all →Frequently asked questions
What does the voltage divider formula calculate?+
It gives you the voltage across one resistor in a series pair fed by a source voltage: Vout = Vin x (R2 / (R1 + R2)), where R2 is the resistor across which you're measuring.
Why does a voltage divider only work reliably with no load, or a very light one?+
The formula assumes no current is drawn from the output node. If you connect a load with a comparable resistance, it forms a parallel combination with R2, changing the effective ratio and lowering Vout below the calculated value.
How do I choose resistor values for a target output voltage?+
Pick a ratio of R2 to (R1+R2) equal to the fraction of Vin you want at the output, then choose absolute resistor sizes based on how much current you can afford to waste — smaller resistors draw more current but load the divider less.
What's a common mistake when using a voltage divider to power a device?+
Treating it as a stable power source. A resistive divider's output voltage sags significantly once any real current is drawn, so it's suited for signal-level sensing (like reading a sensor) rather than powering a load.
Can a voltage divider produce a negative or inverted output?+
Not with standard resistors and a single positive supply — the output is always between 0V and Vin, moving in the same direction as Vin. Producing an inverted voltage requires an active circuit like an op-amp inverter.