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Solar Panel Sizing

Calculate Solar Panel Sizing instantly with the exact formula and a worked example.

Solar Panel Sizing

Consumption, kWh/day
Peak sun hours per day (kWh/m² in the panel plane)
System performance ratio PR%
Power of one panelW
Required power, W
3,125W
P = E / (PSH × PR): peak sun hours are the daily irradiation in kWh/m² in the panel plane (PVGIS or NASA POWER data for your location, and for the darkest season if the system must work all year)PR covers losses from heat, soiling, the inverter and cabling; typically 75–85%Calculate Solar Panel Sizing instantly with the exact formula and a worked example.
Number of panels
8
Installed panel power
3200W
Daily output under these conditions
10.24kWh
Annual output at the same irradiation
3738kWh

More about: Solar Panel Sizing

What it calculates

The “Solar Panel Sizing” calculator computes Required power, W in W from 4 parameters: consumption, kwh/day, peak sun hours per day (kwh/m² in the panel plane), system performance ratio pr (%), power of one panel (W).

A standard physics formula used in educational and engineering tasks.

Example calculation

With parameters Consumption, kWh/day = 10, Peak sun hours per day (kWh/m² in the panel plane) = 4, System performance ratio PR = 80 %, Power of one panel = 400 W the result is 3,125 W (P = E / (PSH × PR): peak sun hours are the daily irradiation in kWh/m² in the panel plane (PVGIS or NASA POWER data for your location, and for the darkest season if the system must work all year)).

How to use

  1. Enter consumption, kwh/day, peak sun hours per day (kwh/m² in the panel plane), system performance ratio pr and power of one panel — each field above is adjustable with a slider.
  2. Required power, W (W) is calculated automatically as you type.
  3. Check the worked example below to see the formula applied to real numbers.
  4. Copy the result or bookmark this calculator.

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FAQ

How is Solar Panel Sizing calculated?
The Solar Panel Sizing calculator computes Required power, W (in W) from consumption, kwh/day, peak sun hours per day (kwh/m² in the panel plane), system performance ratio pr, power of one panel. Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the Solar Panel Sizing calculator free?
Yes. It is completely free, needs no signup, runs entirely in your browser, and sends no data to any server.

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