Solar Energy Output Calculator

Calculator Inputs

System Size (kW)

Enter installed DC system capacity.

Panel Wattage (W)

Used to derive array size.

Panel Count

Panels multiplied by wattage estimate array size.

Peak Sun Hours

Average equivalent full sun hours per day.

Performance Ratio (%)

Captures wiring and real-world conversion effects.

Shading Loss (%)

Tree, roof, or nearby obstruction losses.

Temperature Loss (%)

Higher panel temperature lowers output.

Soiling Loss (%)

Dust, pollen, and dirt reduce production.

Inverter Efficiency (%)

Converts DC energy into usable AC energy.

Tilt and Orientation Factor (%)

Adjusts for installation angle and direction.

Custom Period (Days)

Analyze savings for any selected period.

Electricity Tariff ($/kWh)

Used to estimate financial savings.

Grid Emission Factor (kg CO₂/kWh)

Converts solar generation into avoided emissions.

Reset

Scenario	System Size (kW)	Sun Hours	Net Factor	Daily Output (kWh)	Annual Output (kWh)
Small Roof Array	3.50	4.80	0.73	12.26	4,474.90
Residential Standard	6.00	5.50	0.69	22.77	8,311.05
High Efficiency Setup	8.20	5.90	0.77	37.29	13,611.85

Formula Used

Daily Output (kWh) = System Size (kW) × Peak Sun Hours × Performance Ratio × Inverter Efficiency × Tilt Factor × (1 − Shading Loss) × (1 − Temperature Loss) × (1 − Soiling Loss)

Annual Output (kWh) = Daily Output × 365

System size is the rated solar capacity. Peak sun hours represent equivalent full irradiance hours. Performance ratio captures real operating conditions. Loss percentages reduce theoretical production. Inverter efficiency and tilt factor refine the final usable output estimate.

How to Use This Calculator

Enter the installed system size, or provide panel wattage and panel count.
Add average peak sun hours for the site.
Enter performance ratio and loss percentages for shading, heat, and soiling.
Set inverter efficiency and tilt factor to reflect equipment and orientation quality.
Add tariff and emission factor if you want savings and avoided CO₂ estimates.
Click Calculate Output to view daily, monthly, annual, and custom-period results above the form.
Use the export buttons to download the visible results as CSV or PDF.

FAQs

1. What are peak sun hours?

Peak sun hours convert varying sunlight into equivalent full-strength hours. They are not daylight hours. This metric makes solar production calculations easier and more comparable.

2. Why does performance ratio matter?

Performance ratio reflects real operating conditions beyond nameplate capacity. It accounts for wiring, mismatch, inverter behavior, and other system inefficiencies affecting actual delivered energy.

3. Should I enter both system size and panel details?

You can enter both, but the calculator uses system size first when provided. Panel wattage and count still help verify the estimated array capacity.

4. How do shading losses affect output?

Shading directly reduces incoming solar energy. Even partial shade can lower overall production significantly, especially when strings of panels are electrically connected.

5. What is a good inverter efficiency?

Modern string and microinverters often operate around 95% to 98% efficiency. Higher values improve usable AC output, though real conditions may vary throughout the day.

6. Why is annual output only an estimate?

Actual production changes with seasons, weather, maintenance, degradation, and local conditions. Annual values here are simplified projections based on average daily assumptions.

7. Can this calculator estimate cost savings too?

Yes. Enter your electricity tariff to estimate daily, custom-period, and annual savings. These estimates assume all generated energy offsets purchased electricity at that rate.