Solar Panel kWh Output Calculator
Calculate how much electricity your solar panel system will produce annually and monthly based on location, tilt, and orientation.
Monthly Production Breakdown
| Month | Production (kWh) | % of Annual |
|---|---|---|
| Jan | 707 | 5.5% |
| Feb | 835 | 6.5% |
| Mar | 1,092 | 8.5% |
| Apr | 1,221 | 9.5% |
| May | 1,349 | 10.5% |
| Jun | 1,413 | 11.0% |
| Jul | 1,413 | 11.0% |
| Aug | 1,349 | 10.5% |
| Sep | 1,156 | 9.0% |
| Oct | 964 | 7.5% |
| Nov | 707 | 5.5% |
| Dec | 642 | 5.0% |
| Total | 12,848 | 100% |
How It Works
This calculator estimates your solar system energy production:
- Base production: System size (kW) is multiplied by local peak sun hours, 365 days, and an 80% system efficiency factor to get annual kWh.
- Tilt adjustment: Output is adjusted based on how far your panel tilt deviates from the optimal angle (about 90% of your latitude).
- Orientation adjustment: South-facing panels get 100% of possible output; SE/SW gets 95%; E/W gets 85%.
- Monthly breakdown: Annual production is distributed across months using solar irradiance factors that account for seasonal day-length and sun-angle changes.
Frequently Asked Questions
How many kWh does a solar panel produce per day?
A typical 400W residential solar panel produces 1.2 to 2.6 kWh per day, depending on your location and the amount of peak sun hours. In sunny states like Arizona or California, output is higher; in cloudier states like Ohio or Washington, it is lower.
Does panel orientation affect solar output?
Yes. South-facing panels receive the most sunlight in the Northern Hemisphere and produce the most energy. Southeast or southwest orientations lose about 5% of production, while east or west orientations lose about 15% compared to true south.
How does tilt angle affect solar panel output?
The optimal tilt angle is typically about 90% of your latitude. Panels tilted at the optimal angle can produce 10-25% more energy than flat-mounted panels. Adjusting tilt seasonally can further improve production by up to 5%.
Why does solar output vary by month?
Solar output varies due to changes in day length and sun angle throughout the year. Summer months (May-August) typically produce 50-80% more energy than winter months (November-February) due to longer days and a higher sun angle.