What this calculator does
Voltage divider works out output voltage across the lower resistor of a pair. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaVout = Vin × R₂/(R₁+R₂); current = Vin/(R₁+R₂)
The inputs explained
| Field | What to enter |
|---|---|
| Input voltage (V) | A number, measured in V. Starts at 12. |
| R₁ (top) (Ω) | A number, measured in Ω. Starts at 10000. |
| R₂ (bottom) (Ω) | A number, measured in Ω. Starts at 4700. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with input voltage
Every other input is held at the calculator’s starting values while input voltage varies. Select any row to load that scenario into the calculator.