Electrical calculator
Voltage Divider Calculator
Calculate output voltage from two resistors in series.
About the voltage divider calculator
The voltage divider calculator finds the output voltage from two resistors in series, a fundamental circuit used in sensor interfaces and reference voltages.
How to use this calculator
- 1
Enter input voltage
Enter the source voltage.
- 2
Enter resistor values
Enter R1 (top) and R2 (bottom) resistor values.
- 3
View results
See output voltage, current, and power dissipation in each resistor.
How the calculation works
Vout = Vin × R2 ÷ (R1 + R2). The output is taken across R2.
Example: 5V input, R1=10kΩ, R2=10kΩ = 2.5V output.
Safety first
These calculators provide estimates based on standard formulas and NEC guidelines. Always verify results with a licensed electrician before making installations. Electrical work can be dangerous — never work on live circuits, and always follow local building codes and regulations.
Understanding electrical units
Voltage (V) is electrical pressure, current (A) is flow rate, resistance (Ω) opposes flow, and power (W) is the rate of energy use. Ohm's law (V = I × R) relates the first three, while power formulas (P = VI, P = I²R) connect all four. Understanding these relationships is key to safe electrical design.
Important limitations
This tool provides a mathematical estimate based only on the values entered. It does not account for regulations, taxes, lender fees, market conditions, or individual circumstances. Results are for planning purposes only — consult a qualified professional for regulated, medical, financial, or construction decisions.
Frequently asked questions about voltage divider calculator
How accurate is the voltage divider calculator?+
The calculation follows the displayed formula and retains full numeric precision before formatting the result.
Can I use the result professionally?+
Use it as a planning estimate. Confirm regulated, medical, financial, or construction decisions with a qualified professional.