What angle should my solar panels be? Calculate the optimal tilt angle by latitude and season. Estimate annual energy output, savings, and CO2 offset for your solar array.
Solar Panel Details
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Enter your latitude and panel details for optimal angle
Last updated March 2026 by our expert review team
| Latitude | Annual | Summer | Winter |
|---|---|---|---|
| 25° | 25° | 10° | 40° |
| 30° | 30° | 15° | 45° |
| 35° | 35° | 20° | 50° |
| 40° | 40° | 25° | 55° |
| 45° | 45° | 30° | 60° |
| 50° | 50° | 35° | 65° |
Annual tilt equals latitude. Summer subtracts 15 degrees. Winter adds 15 degrees. Spring/fall equals latitude.
Ehsan Ghazanfari
Licensed Structural Engineer
FISE-certified structural engineer with 11+ years designing bridges, retaining walls, and foundations. MSc from Aalto University.
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Certified Cost & Estimating Professional
AACE-certified estimator working with 20+ insulation companies including the two largest franchises in America.
See full profileUpdated March 2026
How we verify our calculatorsThe simplest rule: set tilt angle equal to your latitude for year-round optimal performance.
Adjustable mounts that change seasonally produce 10 to 15% more energy than fixed mounts.
South-facing panels (180 degrees azimuth) are optimal in the Northern Hemisphere. West-facing loses about 15% annually.
Solar panels reduce cooling loads. Use our BTU calculator to size AC after installing solar.
Clean panels produce 5 to 25% more than dirty ones. Clean at least twice a year, more in dusty areas.
Ground-mounted panels at optimal tilt outperform roof-mounted panels on suboptimal roof pitches by 10 to 20%.
Enter your latitude (check Google Maps if unsure) and select the season you want to optimize for.
Enter the wattage per panel and total number of panels to calculate system size and energy output.
Optionally enter your roof pitch to see how much efficiency you lose compared to the optimal tilt angle.
Solar Angle Formulas
Annual tilt = latitude
Summer tilt = latitude - 15 degrees
Winter tilt = latitude + 15 degrees
Energy = watts x panels x sun hours x 365 x 0.80 efficiency
What angle should solar panels be at?
Set tilt equal to your latitude for annual optimum. At 35 degrees latitude, tilt panels to 35 degrees.
Does roof pitch matter for solar?
Yes. Every degree off the optimal tilt loses about 0.5% efficiency. A roof at 20 degrees with 35 degrees optimal loses about 7.5% vs ground mount.
Should solar panels face south?
In the Northern Hemisphere, yes (180 degrees azimuth). Southern Hemisphere faces north (0 degrees). East/west facing loses 10 to 15%.
How much energy does a 10-panel system produce?
A 10-panel system at 400W each (4kW) produces roughly 5,000 to 7,000 kWh per year depending on location and tilt.
Should I adjust panels seasonally?
Adjustable mounts gain 10 to 15% more energy. Subtract 15 degrees in summer, add 15 degrees in winter. Fixed mounts at latitude are simpler and still effective.
What is peak sun hours?
The number of hours per day when sunlight intensity equals 1,000 W per square meter. This varies from 4 hrs (Seattle) to 7+ hrs (Phoenix).
How much money do solar panels save?
A 4kW system producing 6,000 kWh/year saves about $720/year at $0.12/kWh. Payback is typically 6 to 10 years.
How much CO2 do solar panels offset?
Each kWh of solar replaces 1.22 lbs of CO2 from coal/gas. A 6,000 kWh/year system offsets about 7,300 lbs (3.3 metric tons) annually.
Low latitude means lower tilt angle and more peak sun hours. Southern Florida averages 7+ peak sun hours daily.
Mid-latitude with solid sun exposure. A fixed mount at 33 degrees captures over 95% of maximum annual energy.
High altitude and clear skies help offset the higher latitude. Denver gets more sun than many coastal cities.
Higher latitude and frequent cloud cover reduce output. Seasonal tilt adjustments help capture more winter sun.
Using flat mount (0 degree tilt) instead of latitude angle
A flat panel at 35 degrees latitude loses 10 to 30% of potential energy compared to tilting at 35 degrees. Even a small tilt improves output significantly.
Facing panels east or west instead of south
In the Northern Hemisphere, panels should face due south (180 degrees azimuth). East or west facing loses 10 to 15% of annual production.
Ignoring shading from trees or buildings
Even partial shade from a nearby tree or chimney can cut panel output 25 to 80%. Shade analysis before installation prevents costly surprises.
Not cleaning panels regularly
Dust, pollen, bird droppings, and leaves reduce output 5 to 25%. Clean panels at least twice a year, and more often in dusty or wooded areas.
Over-estimating sun hours for your latitude
National averages do not reflect local weather. Use TMY (Typical Meteorological Year) data for your city, not generic US averages.
Important Disclaimer
These estimates are for planning purposes only. Actual costs vary by location, material availability, and project complexity. Always get at least 3 local quotes. This calculator does not replace professional advice.