PowerUseLab
SOLAR TILT TOOL

Solar Panel Angle Calculator

Estimate a fixed solar panel tilt from latitude, season or month. The result is a planning approximation for a panel facing the equator—not a site-specific irradiance simulation.

Calculate panel tilt

Location is requested only when you press the button. Coordinates are used in your browser and are not stored by this page.

REFERENCE TILT
40°
Facing direction South
Period Annual fixed
Latitude 40° N
Method Tilt ≈ latitude

Monthly solar panel tilt table

These monthly values use the latitude above and the sun's approximate declination on the 15th of each month. They target a surface roughly perpendicular to direct sunlight at solar noon.

Month Solar-noon reference tilt
Jan 61.3°
Feb 52.9°
Mar 42.4°
Apr 30.6°
May 21.2°
Jun 16.7°
Jul 18.5°
Aug 26.2°
Sep 37.2°
Oct 49.0°
Nov 58.4°
Dec 63.3°

How the solar tilt calculation works

For an annual fixed array, tilt approximately equal to absolute latitude is a practical first estimate. Monthly and seasonal modes use solar declination:

δ = 23.45° × sin[(360° ÷ 365) × (284 + n)]

At solar noon, zenith angle is approximately Z = |φ − δ|, where φ is signed latitude and n is day of year. The calculator uses that zenith angle as an approximate panel tilt and constrains the result to 0–90°.

How to interpret the angle

The annual result is a latitude-based starting tilt. Monthly and seasonal results are solar-noon geometric reference tilts for the selected date. In every mode, 0° is flat or horizontal and 90° is vertical. In the Northern Hemisphere, the equator-facing direction is south; in the Southern Hemisphere, it is north.

The estimate does not model shading, roof constraints, diffuse radiation, local weather, bifacial gain, trackers, east/west layouts, time-of-use tariffs or regulations. It does not optimize monthly energy production. A different tilt or direction may better match site conditions or morning and evening demand.

Calculated examples

Latitude 0° Annual tilt: 0°
40° North Annual tilt: 40°, face south
40° South Annual tilt: 40°, face north
40° North, winter About 63.4° near the solstice

Solar panel angle FAQ

What angle should solar panels be installed at?

For a fixed annual array, absolute latitude is a practical first estimate. Shading, roof geometry and energy goals can justify another angle.

Should solar panel tilt equal latitude?

It is a useful annual starting point, not a universal optimum.

What angle is best for solar panels in winter?

Winter sun is lower, so a steeper tilt is generally appropriate. This calculator estimates it from latitude and solar declination.

Which direction should solar panels face?

For a general annual recommendation, face toward the equator: south in the Northern Hemisphere and north in the Southern Hemisphere.

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