wattbench
Engineering Tool

Solar Panel Power Density Calculator

From rated power and module dimensions, compute power density in W/m², module efficiency and panels needed per kilowatt.

Sources listedReviewed July 2026Our methodology

Inputs

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Panel nameplate (STC) power.

Live result

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Power density

225W/m²

Module efficiency

22.5%

Panel area

1.95m²

Panels per kW

2.3

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Key takeaways
  • Computes power density in watts per square metre from a panel's rated power and dimensions.
  • Also returns module efficiency and how many panels are needed per kilowatt.
  • Useful for comparing how much power different modules pack into the same area.

How it works

Power density is rated power spread over the panel's physical area: density = power ÷ (length × width), in watts per square metre.

  • Module efficiency is that density measured against standard test conditions: efficiency = density ÷ 1000 W/m² × 100. STC assumes 1000 W/m² of irradiance.
  • Panels per kW is simply 1000 ÷ rated watts, handy for sizing.

Estimates only: for guidance, not a quote or a compliance certificate. Verify against the current AS/NZS standards and a licensed design. The maths runs in your browser. Nothing is sent to Wattbench unless you sign in and deliberately save the result.

Source ledger3 sources

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Frequently asked

Is this calculator free to use?
Yes. The power density calculator is free and needs no sign-up. It runs entirely in your browser.
Is my data stored or sent anywhere?
The calculation runs in your browser. Nothing is sent to Wattbench unless you sign in and deliberately select Save result.
What do I need to calculate power density?
You need a module's rated power and its dimensions. From those the tool estimates power density, module efficiency and panels per kilowatt.
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