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Solar System Size Calculator

Convert daily electricity consumption into a planning solar-array size and panel quantity using your own solar-resource, system-loss and panel assumptions.

Solar design assumptions
Peak sun hours are not daylight hours. Enter a planning value appropriate to the project's location, season and available solar-resource evidence. Overall efficiency represents combined real-world losses such as temperature, inverter/conversion, wiring, mismatch, dirt and other system effects. These assumptions are editable rather than treated as universal Nigerian values.
Waiting for calculation
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Your solar-array planning result will appear here after you click the button.

—daily electricity demand
—base PV capacity
—PV capacity incl. margin
—whole solar panels
Selected panel rating—
Installed panel nameplate capacity—
Peak sun hours / system efficiency—
Estimated daily energy from installed array—
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Carry the calculated panel quantity and array capacity into supported solar-equipment price intelligence.

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Find solar suppliers / installers

Use the calculated energy and solar-array requirement to request suitable solar businesses and Quotes or Offers.

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Solar design boundary: This calculator sizes PV energy production at a planning level only. It does not size batteries, inverter continuous/surge power, charge controllers, strings, MPPT voltage/current, cables, protection, earthing, mounting structure or roof loading. Shading, orientation, tilt, temperature, weather variability, module degradation, generator/grid charging and autonomy requirements can materially change a real system. Final equipment selection should be based on a site-specific electrical and solar design.

How the calculation works

Base PV capacity (kW) = daily energy demand (kWh) ÷ [peak sun hours × overall system efficiency]. The selected sizing margin is then added. Panel quantity is the required array watts divided by panel wattage, rounded up to a whole panel. The resulting installed nameplate capacity and approximate daily yield are shown separately. Battery and inverter sizing are deliberately left for their dedicated calculators.

How to Use and Check Your Result

Enter the measurements, quantities, costs and assumptions requested in the calculator above. Use its calculation control and review the displayed result. All figures should be checked against your actual project or operating conditions.

Planning and safety: Electrical or power-system sizing requires qualified design review and applicable safety standards. Finelib does not certify engineering designs or supplier quotations.

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Frequently Asked Questions

What does the Solar System Size Calculator estimate?

It estimates planning quantities or costs from the figures you enter. Review the calculator assumptions before using the result.

Can I use this calculator for a project in Nigeria?

Yes. Enter measurements and quotations relevant to your Nigerian location and project.

Does Finelib supply current market prices automatically?

No. Prices and rates should be checked with relevant suppliers; do not assume any illustrative values are live quotations.

Are the results guaranteed to be accurate?

No. The output depends on entered assumptions and is intended for preliminary planning, not professional certification.

How should I handle wastage or losses?

Where the calculator provides a wastage or contingency field, enter an allowance appropriate to the project. Otherwise account for it separately.

Can I use the result to request supplier quotes?

Yes. Use Finelib Match to find suitable businesses and request Quotes or Offers, then verify specifications and providers.

Should a professional review the result?

Yes, when the decision involves structural safety, electrical safety, major equipment, significant expenditure or regulatory requirements.