Solar Panel Output Calculator (by Location). Enter your location coordinates, panel specifications, and tilt angle to calculate your expected solar panel output. Provide your latitude, longitude, panel wattage, number of panels, tilt angle, and panel efficiency — and get back your estimated daily kWh output, monthly generation, annual energy production, and CO₂ offset based on your geographic solar irradiance. Also try the Community Solar Calculator.
Latitude determines the angle at which sunlight hits your location and the number of daylight hours throughout the year. Locations closer to the equator (lower latitude) generally receive more consistent solar irradiance year-round. Higher latitudes experience greater seasonal variation, with longer summer days but much shorter winter days, affecting annual average output. See also our calculate Solar ROI Payback Period.
The optimal tilt angle for maximum annual energy production is typically close to your latitude in degrees. For example, if you're at 35° North latitude, a tilt of around 30–35° is generally optimal. Steeper tilts can favor winter production, while flatter tilts favor summer production. In the Southern Hemisphere, panels should face North.
Peak sun hours represent the number of hours per day when sunlight intensity averages 1,000 W/m² (the standard test condition for solar panels). A location with 5 peak sun hours receives the equivalent of 5 hours of full-intensity sunlight daily. This calculator estimates peak sun hours from latitude, seasonal variation, and tilt angle — it's not the same as total daylight hours.
Real solar systems lose energy due to several factors: inverter inefficiency (~4%), wiring resistance (~2%), temperature effects (~5%), soiling and dust (~2%), shading (~2%), and mismatch losses (~2%). The total system loss is typically 10–20%, with 14% being a commonly used default value based on NREL's PVWatts calculator methodology. You might also find our calculate Solar Panel Efficiency Panel Efficiency useful.
Azimuth determines how much direct sunlight your panels receive throughout the day. In the Northern Hemisphere, south-facing panels (180° azimuth) receive the most sunlight and produce the highest annual output. East-facing panels generate more in the morning, west-facing panels in the afternoon. Deviating significantly from south can reduce output by 10–20%.
This calculator uses established solar energy formulas based on latitude-derived irradiance, tilt correction factors, and azimuth adjustments to provide a reasonable estimate. Results should be within 10–20% of actual production for most locations. For precise project planning, we recommend consulting a professional installer who uses tools like NREL's PVWatts or NASA's POWER database with local weather data.
The CO₂ offset is estimated using the US EPA's average grid emission factor of approximately 0.386 kg CO₂ per kWh of electricity generated. Your annual solar output (kWh) is multiplied by this factor to show how much carbon dioxide your system displaces compared to grid electricity. The actual offset varies by region depending on your local energy mix.
System capacity in kilowatt-peak (kWp) is the rated maximum power output of your solar array under standard test conditions (STC: 1,000 W/m², 25°C). It equals the total number of panels multiplied by each panel's wattage. Actual output (kWh) is lower because it accounts for real-world conditions like varying sunlight, temperature, and system losses — it's what you actually generate and consume. Check out our Solar Panel Calculator as well.