Solar Panel Power Output Calculator
Estimate the electrical power from a solar panel: P = G · A · η (irradiance × area × efficiency).
Inputs
Drag the handle (or focus it and press ↑/↓) to reorder. Scientific notation such as 1e3 is accepted. Pick any unit; conversion is automatic.
Results
Enter values and press Calculate. Your answer will appear here.
Power output vs. irradiance
Power rises in direct proportion to irradiance for a given panel. The dot is your input. If you added temperature or loss derating, the dashed line is the ideal output without it.
What is being calculated
Common examples
| Case | G | A | η | P |
|---|
Illustrative inputs, not manufacturer data.
Output of a 1.7 m², 20 % panel at different irradiance
| Irradiance G | Power P | Of 1-sun rating |
|---|
Reference conditions
| Condition | Irradiance | Other |
|---|---|---|
| STC (standard test conditions) | 1000 W/m² | cell 25 °C, AM1.5 |
| NOCT (nominal operating cell temp.) | 800 W/m² | air 20 °C, 1 m/s wind |
| Heavy overcast (approx.) | ≈ 100–300 W/m² | varies with cloud |
Unit conversions
| Quantity | Conversion |
|---|---|
| Irradiance | 1 sun = 1000 W/m² · 1 kW/m² = 1000 W/m² · 1 mW/cm² = 10 W/m² · 1 W/ft² = 10.764 W/m² |
| Area | 1 m² = 10,000 cm² = 10.764 ft² · 1 ft² = 0.092903 m² · 1 in² = 6.4516×10⁻⁴ m² |
| Power | 1 kW = 1,000 W · 1 MW = 1,000 kW |
| Energy | 1 kWh = 1,000 Wh = 3.6 MJ |
Formula
- P: electrical power output (W)
- G: solar irradiance on the panel surface (W/m²)
- A: panel area (m²)
- η: panel efficiency (0 to 1, or 0 to 100 %)
Example: G = 1000 W/m², A = 1.7 m², η = 20 %. P = 1000 × 1.7 × 0.20 = 340 W.
Datasheet efficiency is measured at standard test conditions (1000 W/m², 25 °C cell). Real output is usually lower. Advanced mode applies two common corrections: P = G·A·η·[1 + γ(Tcell − 25 °C)]·(1 − L), where γ is the power temperature coefficient and L the combined system loss. With hours per day, energy is E = P × hours; the annual figure assumes the same output every day. The calculator does not model shading, panel angle or sun position, so use measured irradiance on the panel plane.
References
- PVEducation, Standard Test Conditions: 1000 W/m², 25 °C, AM1.5
- NREL, Best Research-Cell Efficiency Chart: cell and module efficiencies
- NREL PVWatts Calculator: system losses and energy estimates
How to Use This Tool
- Pick a preset, or enter the irradiance G and its unit (1 sun = 1000 W/m²).
- Enter the panel area A and the efficiency η from the datasheet.
- In Advanced, use length × width, set the number of panels, and add cell temperature, γ, system losses or hours per day.
- Click Calculate.
- Read P in the highlighted result and check the power-vs-irradiance chart.
What This Tool Offers
- Basic and Advanced modes on one calculation engine
- Irradiance, area, temperature and power unit conversion
- Output compared with the 1-sun (STC) rating
- Panel count, temperature derating, system losses and daily, monthly and annual energy (Advanced)
- Power-vs-irradiance chart and labelled solar panel diagram
- Reorderable inputs, presets and a mobile-friendly layout
Variables
| Symbol | Quantity | Unit |
|---|---|---|
| P | Solar panel power output (DC) | W |
| G | Solar irradiance (incident solar power per unit area) | W/m² |
| A | Surface area of the solar panel | m² |
| η | Solar panel conversion efficiency (decimal used in calculation) | % (expressed as decimal in formula) |
What it means
The power output of a solar panel is P = Irradiance × Area × Efficiency, where irradiance is the solar power per unit area (typically 1000 W/m²), Area is the panel’s active surface area (m²), and Efficiency is the conversion efficiency of the cells. This gives the DC output power under standard test conditions (STC). Example: A panel with area 1.6m² and efficiency 18% under 1000 W/m² produces P = 1000 × 1.6 × 0.18 = 288 W. Real‑world output is lower due to temperature, shading, and orientation. This calculation is used for sizing PV systems.
Worked example
Solar Panel Output – Practical Example
Real‑World| Parameter | Value |
|---|---|
| Irradiance G | 1000 W/m² |
| Area A | 1.6 m² |
| Efficiency η | 18% = 0.18 |
| Formula | P = G × A × η |
Common mistakes
Watch for unit mismatches (W vs kW, single- vs three-phase) and remember to include power factor or efficiency where the formula requires it.Applications
Solar panel power output P = Irradiance × Area × Efficiency estimates the DC power of a PV panel under standard conditions. This is used in PV system design and sizing. Engineers use it to calculate energy yield, to select panels, and to optimise layouts. This formula is fundamental for solar energy projects.
- PV system sizing and energy yield prediction
- Solar panel selection and performance evaluation
- Feasibility and economic analysis of solar projects
- Design of rooftop and utility‑scale solar farms
- Educational understanding of solar energy conversion
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