Free Solar Panel Tilt Angle Calculator
Calculate optimal fixed year-round, winter, summer, and spring/fall photovoltaic tilt angles and inter-row spacing to prevent shading.
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📊 Recommended Angles & Row Spacing
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Frequently Asked Questions
What is the rule of thumb for solar panel tilt angle?
The general rule of thumb for a fixed annual solar panel tilt angle is equal to your latitude. For better annual optimization, multiply latitude by 0.76 and add 3.1 degrees. For winter optimization, add 15 degrees to your latitude.
Which direction should solar panels face in the Northern Hemisphere?
In the Northern Hemisphere, solar panels should face True South (180° azimuth). In the Southern Hemisphere, panels should face True North (0° azimuth). Note that True South differs from Magnetic South by your local magnetic declination angle.
How far apart should rows of solar panels be spaced?
Inter-row spacing must be wide enough so the front row does not cast a shadow on the back row at solar noon on the shortest day of the year (December 21st in the Northern Hemisphere). The required distance D = Panel Height × sin(Tilt) / tan(Winter Noon Solar Altitude).
Do solar panels work on a flat roof without tilting?
While solar panels generate electricity when mounted flat (0° tilt), a minimum tilt of 10 degrees is strongly recommended. Flat panels allow rainwater, dirt, pollen, and leaves to pool on the glass, creating severe soiling degradation of 10% to 25% over time.