When to use this calculator
Convert a nominal solar-array power target into whole panel count. Nameplate sizing only; roof layout, inverter compatibility and expected energy yield are separate.
Explore the solar generation & value calculators for other questions in this topic. For a related calculation, use the Solar Parallel Short Circuit Current Calculator: Sum short-circuit current assumptions for equal parallel solar strings.
PUTTING IT INTO PRACTICE
Solar Panel Count: 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 |
|---|---|
| Target nominal array size (kW) | 5 |
| Nominal panel rating (W) | 400 |
| Result | 13 panels |
- Check the input labels and enter the example values above.
- Apply the relationship: Panel count = ceiling(target kW×1000/panel watts).
- The result is 13 panels, rounded for display.
How to interpret your result
Nameplate sizing only; roof layout, inverter compatibility and expected energy yield are separate.
Peak sun hours describe equivalent full-power sunlight, not total daylight. Self-consumption and self-sufficiency have different denominators. On-site use and exports may have different monetary values.
Frequently asked questions
Are self-consumption and self-sufficiency the same percentage?
No. Self-consumption divides solar used on site by solar generated; self-sufficiency divides solar supplying demand by total site demand.
When is the solar panel count calculator useful?
Convert a nominal solar-array power target into whole panel count. Nameplate sizing only; roof layout, inverter compatibility and expected energy yield are separate.
How do I use the solar panel count calculator?
Enter target nominal array size (kw), nominal panel rating (w). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Panel count = ceiling(target kW×1000/panel watts).
What should I check before using the result?
Nameplate sizing only; roof layout, inverter compatibility and expected energy yield are separate.
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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