Solar planning

Solar Panel Tilt Calculator

Find a practical starting tilt for your solar panels from your latitude, then optionally compare your existing roof angle with a location-based production model.

Find a starting panel angle

Quick Locations:

What angle should solar panels be tilted?

A simple year-round starting estimate is the absolute value of your latitude. For example, a location at 34° north starts with a 34° panel tilt and a south-facing orientation. This is a planning starting point, not a universal optimum.

Solar panel angle by latitude reference chart

The optimal tilt angle depends on whether you want to maximize year-round solar energy production or optimize for seasonal peaks (higher in winter when the sun is low, lower in summer when the sun is high):

Optimal solar panel tilt angle by latitude
Latitude / Region	Summer Tilt (Latitude − 15°)	Year-Round Optimum (Latitude)	Winter Tilt (Latitude + 15°)	Orientation Direction
25° N (Miami, Taipei, Dubai)	10°	25°	40°	True South (180°)
30° N (Houston, Cairo, New Delhi)	15°	30°	45°	True South (180°)
34° N (Los Angeles, Atlanta, Sydney 34° S)	19°	34°	49°	South (North for S Latitudes)
40° N (New York, Madrid, Denver)	25°	40°	55°	True South (180°)
45° N (Minneapolis, Milan, Montreal)	30°	45°	60°	True South (180°)
52° N (London, Berlin, Calgary)	37°	52°	67°	True South (180°)

Tilt versus azimuth

Tilt is the panel angle above horizontal. Azimuth is the compass direction the panels face. The quick estimate suggests an equator-facing direction, while the roof comparison lets you enter your actual roof tilt and orientation.

How to compare an existing roof angle

Turn on Compare my roof, enter the roof tilt and choose its orientation. The local result remains available immediately. When modeled comparison is used, both geometries keep the same system assumptions so the difference isolates the roof geometry as much as the model allows.

How the production comparison works

The optional comparison uses PVWatts V8 location-aware modeling with a normalized 1 kW system by default. It can show modeled annual and monthly AC production, but it is an estimate based on historical weather and system assumptions—not a guarantee of actual output.

Solar Panel Tilt Angle Formulas

Calculates optimal fixed solar panel tilt relative to horizontal based on geographic latitude and Earth's 23.45° axial tilt declination cycle.

FormulaYear_Round = Latitude × 0.76 + 3.1° | Summer = Latitude - 15° | Winter = Latitude + 15°

Variable Definitions

LatitudeGeographic Latitude(degrees): Distance north (+) or south (-) from Earth's equator.
Year_RoundFixed Annual Optimal Tilt(degrees): Maximizes cumulative annual kilowatt-hour solar harvest for fixed mounts.
SummerSummer Peak Optimization(degrees): Flatter angle optimized for higher summer solar elevation.
WinterWinter Peak Optimization(degrees): Steeper angle optimized for lower winter sun trajectories and snow shedding.

Engineering Notes & Standards

Equator-facing azimuth orientation: 180° (True South) in the Northern Hemisphere; 0° (True North) in the Southern Hemisphere.
A tilt angle deviation of ±10° from optimal typically causes less than 3% to 5% loss in total annual solar generation.

Frequently Asked Questions (FAQ)

What is the best angle for solar panels?

For year-round solar energy production on a fixed mount, the ideal tilt angle is approximately equal to your geographical latitude (e.g. 35° tilt at 35° latitude). For seasonal optimization, subtract 15° in summer and add 15° in winter.

Should I adjust my solar panel tilt between summer and winter?

For roof-mounted residential systems, the minor 3%–6% annual production boost usually does not justify the cost and labor of manual adjustments. For ground mounts or off-grid systems with high winter heating needs, seasonal 2-position or 4-position adjustments can be very beneficial.

Which direction should solar panels face?

In the Northern Hemisphere, solar panels should face True South (180° azimuth). In the Southern Hemisphere, they should face True North (0° azimuth). Facing East or West typically produces 15%–25% less annual energy.

Is it worth modifying roof pitch for solar panels?

No. Standard roof pitches (between 15° and 40°) typically capture 90%–98% of maximum theoretical solar energy. Modifying roof structural framing is rarely cost-effective compared to adding 1 or 2 extra panels.

How to improve the estimate

Use your actual latitude, roof tilt and azimuth, system size, known losses and inverter details. Shading, roof constraints, temperature, equipment and local weather can change the best practical setup.

Read the methodology and sources for the calculation and model references.