Solar Panel Angle Calculator

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Enter your latitude to find a year-round solar panel tilt, seasonal angle suggestions, and the best direction to face the panels.

Advanced options
Roof comparison

Summer subtracts this offset from absolute latitude; winter adds it. Targets are limited to 0–90 degrees. This is a planning heuristic, not a production forecast.

Enter 0 for no rounding. Otherwise the setting is the nearest available step from horizontal, no higher than 90 degrees. Confirm actual hardware limits.

Recommended year-round panel tiltdegrees from horizontal
A simplified fixed-angle planning target based on latitude.
Recommended facing direction
Use true north or true south, not magnetic compass direction.
Suggested summer tiltdegrees from horizontal
Suggested winter tiltdegrees from horizontal
Suggested spring and fall tiltdegrees from horizontal
Selected-season targetdegrees
Suggested mount settingdegrees
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How to use our Solar Panel Angle Calculator

  1. Find your decimal latitude in a maps app or location details. Enter a positive number north of the equator or a negative number south of it.
  2. Type the number in "Latitude (degrees)" and select "Calculate."
  3. Read "Recommended year-round panel tilt" as an angle measured up from level horizontal ground, not from a wall or vertical line.
  4. Check the facing direction and seasonal suggestions only if the mounting system can be adjusted safely.
  5. To check a roof, open "Advanced options." Choose the matching comparison type, enter the roof pitch or measured angle, and use the signed gap to see whether it is steeper or shallower than the annual target.
Example inputs for Solar Panel Angle Calculator
Example inputs for Solar Panel Angle Calculator

Definitions

Latitude: A location's distance north or south of the equator, in degrees. North is positive; south is negative.

Panel tilt: The panel angle measured up from horizontal. A flat panel is 0 degrees, and a vertical panel is 90 degrees.

Year-round tilt: A single fixed panel angle used as a simple planning target for the whole year.

Rise in 12: A US roof-pitch measurement showing vertical rise over 12 inches of horizontal run. A 6-in-12 roof rises 6 inches over a 12-inch run.

True south / true north: Geographic directions based on the Earth's poles. They can differ from magnetic compass directions.

Roof angle gap: The entered roof or panel angle minus the year-round target. A positive gap is steeper, while a negative gap is shallower.

Seasonal panel tilt guideUse the year-round latitude target as the center setting; adjust 15 degrees for summer or winter. Tilt is measured in degrees up from horizontal and is limited to 0 through 90 degrees.Seasonal panel tilt guideUse the year-round latitude target as the center setting; adjust 15 degrees for summer or winter.SummerYear-roundWinter0 degrees30 degrees60 degrees90 degreesPanel tilt from horizontal (degrees)
Seasonal panel tilt guide
Tilt is measured in degrees up from horizontal and is limited to 0 through 90 degrees.

Common mistakes and quick fixes

Mistake: Leaving out the latitude sign.
Fix: Use a positive latitude north of the equator and a negative latitude south of the equator.

Mistake: Entering a 6-in-12 roof pitch as 6 degrees.
Fix: Choose "Roof pitch in rise per 12" and enter 6. The calculator converts it to about 26.6 degrees.

Mistake: Measuring panel tilt from vertical.
Fix: Measure upward from a level horizontal line. Flat is 0 degrees, and vertical is 90 degrees.

Mistake: Pointing panels by magnetic compass alone.
Fix: Use true south north of the equator or true north south of it. A compass may need a local magnetic-declination correction.

Mistake: Treating the angle as a production forecast.
Fix: Use it as a starting point. Check shade, roof direction, mounting limits, weather, and system design separately.

Limitations & Key Assumptions / Boundary Conditions

  • This calculator uses a simple latitude rule for early planning; it does not estimate energy production or guarantee the best site-specific angle.
  • Seasonal offset (degrees) defaults to 15 and is adjustable in Advanced options. Seasonal suggestions and mount settings are only relevant for mounts that can be changed safely.
  • Shade, roof direction, nearby obstacles, weather, panel spacing, and electricity use can change the practical system design.
  • Use true north or true south for direction. Magnetic compass readings can differ because of local magnetic declination.
  • The roof comparison checks angle only. It does not evaluate roof strength, wind or snow loads, drainage, permits, electrical design, or mounting approval.
  • Latitude must be from -90 through 90 degrees. Measured tilt must be from 0 through 90 degrees. Roof rise can be 0 or greater.

Methodology

Calculation method

The calculator uses the absolute value of latitude, meaning the distance from the equator without the north-or-south sign. That distance becomes the simplified year-round tilt, while the sign determines the recommended facing direction.

year-round tilt = absolute value of latitude

For positive latitude, the guide recommends facing panels toward true south. For negative latitude, it recommends true north. At 0 degrees latitude, it does not choose between north and south because site conditions matter.

Seasonal settings

Summer subtracts Seasonal offset (degrees) from the annual target, with a minimum of 0 degrees. Winter adds that offset, with a maximum of 90 degrees. Spring and fall use the annual target. Season for mount setting chooses the target for rounding; it does not change the existing annual roof comparison.

summer tilt = max(0, year-round tilt - seasonal offset)

winter tilt = min(90, year-round tilt + seasonal offset)

spring and fall tilt = year-round tilt

Roof comparison

A rise-in-12 roof pitch is converted to an angle from horizontal before comparison. The roof angle gap is the entered or converted angle minus the year-round target, so a negative value means the surface is shallower.

roof angle = arctangent(rise / 12) x 180 / pi

roof angle gap = roof or panel angle - year-round tilt

Worked example

For latitude 40 degrees, the year-round target is 40.0 degrees and the direction is true south. Summer is 25.0 degrees, winter is 55.0 degrees, and spring and fall are 40.0 degrees. A 6-in-12 roof converts to about 26.6 degrees, producing a -13.4 degree gap, so it is shallower than the annual target.