Enter system size and sunlight
Use the combined DC capacity of all panels in kilowatts. Peak sun hours describe solar energy intensity, not the number of daylight hours.
Solar Panel Output Estimator Online
Estimate how much electricity your solar panels could produce, how much of your usage they may cover, and what that energy could save each year.
Your estimate stays on this deviceYour solar outlook
Based on a 6 kW system and 4.5 peak sun hours
Estimated annual solar energy8,475 kWh
About 706 kWh per month and 23.2 kWh on an average day.
88%of usage
Average daily output23.2 kWh
Average monthly output706 kWh
Estimated annual savings$1,356
Approximate panel count15 panels
A promising starting point. This setup could cover most of the electricity use you entered.
Illustrative monthly production
Seasonal shape for the Northern Hemisphere
Planning estimate only. Weather, temperature, snow, equipment, roof geometry, local rules and utility billing can change real production and savings.
A clear estimate in three steps1 2 3
How to estimate solar panel output
This solar panel output estimator converts a few real-world inputs into an approachable energy forecast. It starts with the rated size of the system and the peak sun hours available at the site, then reduces the theoretical output for roof direction, tilt, shading and typical system losses.
Adjust the roof conditions
Choose the closest roof direction and tilt, then estimate how much daytime shade reaches the panel area.
Compare energy and usage
See daily, monthly and yearly solar production alongside panel count, bill coverage and a simple savings estimate.
Understanding your solar energy estimate
A panel's watt rating shows its output under standard test conditions. A complete system rarely operates at that rating all day, so a useful estimate combines installed kilowatts with peak sun hours. Direction, tilt and shade change how much sunlight reaches the array, while system losses account for energy that does not reach the meter.
Estimator formulaSystem kW × peak sun hours × 365 × roof factors × (1 − losses)
The result is an annual energy estimate in kilowatt-hours (kWh). The monthly bars are an illustrative seasonal distribution of that same annual total; they are not a weather forecast.
What makes the estimate more accurate?
Use a local solar resource map or installer report for peak sun hours, check shading across the full year, and enter the actual panel and inverter specifications when available. For a final decision, compare this online solar output calculator with a professional site survey that includes roof dimensions, obstructions, local climate, equipment behavior and utility tariffs.
Solar panel output estimator FAQ
How do I estimate solar panel output?
Multiply the system size in kilowatts by daily peak sun hours, then adjust for direction, tilt, shade and equipment losses. Multiply the adjusted daily output by 365 for an annual estimate.
What are peak sun hours?
Peak sun hours express a day's solar energy as the equivalent number of hours at an intensity of 1,000 watts per square meter. They are different from total daylight hours and vary by location and season.
How many solar panels do I need?
The estimator divides your target system wattage by the wattage of one panel and rounds up. The actual count can change with roof area, panel dimensions, layout setbacks, local codes and equipment compatibility.
Why can actual solar production differ?
Cloud cover, temperature, dirt, snow, panel aging, inverter clipping, wiring, roof geometry and unexpected shade can all affect real output. Treat the result as a scenario, not a guarantee.
Does solar output equal electricity bill savings?
Not always. Savings depend on when you produce and use electricity, the utility rate structure, export compensation, fixed charges and any batteries. This tool applies one price to each estimated kilowatt-hour for a simple comparison.
Is this solar panel output estimator online free?
Yes. The calculator is free to use online, needs no account and saves your last inputs only in your browser.
Try other planning tools
Connect your solar estimate with long-term growth and everyday household planning.