Voltage Divider Calculator
Output voltage, current and power for a two-resistor divider.
Enter your values
ⓘ Live results
Results
- Output voltage
- 3.8367 V
- Current through the divider
- 0.8163 mA
- Power in R1
- 6.664 mW
- Power in R2
- 3.132 mW
- Total power
- 9.796 mW
- Divider output impedance
- 3197.3 Ω
Quick answer
A resistive divider outputs Vin × R2 ÷ (R1 + R2), so the voltage splits in proportion to the resistances.
Vout = Vin × R2 ÷ (R1 + R2)
How to use the Voltage Divider Calculator
- 1Enter the supply voltage.
- 2Enter both resistor values in ohms.
- 3Add a load resistance to see how much the output sags under real use.
Frequently asked questions
Why does my divider sag under load?
The load sits in parallel with R2, lowering the effective bottom resistance. Keep the load at least 10× R2, or buffer it with an op-amp.
How do I pick resistor values?
Lower values waste more current but resist loading better. For sensing, tens of kilohms is a common compromise.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.