When to use this calculator
Estimate unloaded output voltage from a two-resistor divider. Assumes no load connected to the output; a load changes the voltage.
Explore the dc circuits & components calculators for other questions in this topic. For a related calculation, use the Voltage Drop DC Calculator: Estimate resistive voltage drop using current and total loop resistance.
PUTTING IT INTO PRACTICE
Voltage Divider: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Input voltage (V) | 12 |
| Upper resistance (Ω) | 10,000 |
| Lower resistance (Ω) | 5,000 |
| Result | 4 V |
- Check the input labels and enter the example values above.
- Apply the relationship: Output = input × lower resistance ÷ (upper + lower).
- The result is 4 V, rounded for display.
How to interpret your result
Assumes no load connected to the output; a load changes the voltage.
Ideal component models omit tolerances, heat and parasitic effects. Distinguish nominal energy from usable energy for batteries. Component ratings and installation requirements need separate manufacturer and design checks.
Frequently asked questions
Can these calculations select a safe installation rating?
No. They explain ideal relationships and do not include every thermal, protective or regulatory requirement.
How do I use the voltage divider calculator?
Enter input voltage (v), upper resistance (ω), lower resistance (ω). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Output = input × lower resistance ÷ (upper + lower).
What should I check before using the result?
Assumes no load connected to the output; a load changes the voltage.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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