What angle should solar panels be tilted?

The US Department of Energy’s guidance for fixed panels in the Northern Hemisphere is due south at a tilt equal to the local latitude for the highest annual output. At 35° latitude this page gives 35° for a fixed mount, 20° in summer and 50° in winter for a seasonal setting, and 31.5° for the year-round rule. Real sites depend on shading, roof pitch and weather.

What is the seasonal tilt adjustment?

Subtract 15° from the latitude for the summer setting and add 15° for the winter setting, each kept between 0° and 90°. At 40° that is 25° and 55°. At 10° latitude the summer tilt is 0°, because 10 − 15 is below zero.

Which direction should the panels face?

True south in the Northern Hemisphere (azimuth 180°) and true north in the Southern (azimuth 0°). A compass points to magnetic north, so correct for the local magnetic declination before you set the direction.

Should I use the latitude or 0.9 × latitude?

Start from the latitude: it is the fixed tilt the Department of Energy gives for the highest annual output. The 0.9 × latitude figure is a simple approximation that lands a little lower, 36° instead of 40° at 40°N. This page found no published source that establishes it, so treat it as a variant to compare, not a better answer.

What angle should solar panels be at each month?

Latitude minus the sun’s declination in the middle of the month, so the panel faces the noon sun. At 40°N the page gives 61.3° in January, 42.8° in March, 16.9° in June, 38.2° in September and 63.1° in December. A fixed mount cannot follow this; use it to decide when an adjustable rack is worth moving.

Does the page estimate how much power I will get?

No. It has no weather, shading or yield model and shows no energy figure, so it cannot say how much a few degrees off the rule would cost.

Solar Panel Tilt Angle Calculator

Solar panel tilt and azimuth from your latitude or a city: tilt = latitude for a fixed mount, ±15° by season, a tilt for each month. No yield estimate. How it works

Latitude (degrees)

Range: -90° (South Pole) to 90° (North Pole). Positive for Northern hemisphere.

Or pick a city

Fills the latitude field from a bundled list (to 0.1°). You can still type any latitude.

Mounting Mode

Tilt

40°

Azimuth 180° true south

These are rules of thumb for tilt and azimuth, not an optimised design. This tool does not estimate energy yield. Shading, local weather, roof pitch and the installer's design decide the real tilt. The azimuth assumes the panels face the equator in the Northern hemisphere.

All three rules at 40.0° latitude

Mount	Tilt (degrees)
Fixed Mount (tilt = latitude)	40
Seasonal Adjust (latitude ∓ 15, summer / winter)	25 / 55
Year-Round Rule (0.9 × latitude)	36

Tilt for each month at 40.0° latitude

Month	Tilt (degrees)	Faces
January	61.3	true south
February	53.3	true south
March	42.8	true south
April	30.6	true south
May	21.2	true south
June	16.9	true south
July	18.8	true south
August	26.5	true south
September	38.2	true south
October	50.0	true south
November	59.1	true south
December	63.1	true south

Rule of thumb: tilt = latitude minus the sun's declination in the middle of the month, so the panel points at the sun at solar noon. A fixed mount cannot follow it; use it as a guide for re-tilting by season.

About the Solar Panel Tilt Angle Calculator

At 40°N the usual starting point for a fixed solar panel is a tilt of 40°, equal to the latitude, facing true south (azimuth 180°). If you re-tilt twice a year, use 25° for summer and 55° for winter. A flatter fixed angle of 0.9 times latitude gives 36°. In the Southern Hemisphere the panels face true north (azimuth 0°).

The three tilt rules by latitude (Northern Hemisphere)

Latitude	Fixed mount	Seasonal: summer	Seasonal: winter	Year-round rule
10°	10°	0°	25°	9°
20°	20°	5°	35°	18°
30°	30°	15°	45°	27°
40°	40°	25°	55°	36°
50°	50°	35°	65°	45°
60°	60°	45°	75°	54°

Tilt in degrees from horizontal, facing true south. A Southern Hemisphere latitude gives the same tilts with the azimuth at 0°, true north. Seasonal tilts are kept between 0° and 90°.

Tilt for each month (Northern Hemisphere)

Month	30°N	40°N	50°N
January	51.3°	61.3°	71.3°
February	43.3°	53.3°	63.3°
March	32.8°	42.8°	52.8°
April	20.6°	30.6°	40.6°
May	11.2°	21.2°	31.2°
June	6.9°	16.9°	26.9°
July	8.8°	18.8°	28.8°
August	16.5°	26.5°	36.5°
September	28.2°	38.2°	48.2°
October	40.0°	50.0°	60.0°
November	49.1°	59.1°	69.1°
December	53.1°	63.1°	73.1°

Latitude minus the solar declination on the day the page uses for each month, so the panel faces the sun at solar noon. A rule of thumb for re-tilting by hand, not an optimized schedule. In the Southern Hemisphere the months swap: at 34°S the page gives 57.1° in June and 10.9° in December.

How to use this tool

Type your latitude, from −90 to 90, or pick one of 64 cities to fill it in. The page starts at 40.
Choose Fixed Mount, Seasonal Adjust or Year-Round Rule.
Read the tilt, or the summer and winter tilts for Seasonal Adjust, and the azimuth. The tables below the result show all three rules at your latitude and a tilt for each month.

Frequently asked questions

What angle should solar panels be tilted?: The US Department of Energy’s guidance for fixed panels in the Northern Hemisphere is due south at a tilt equal to the local latitude for the highest annual output. At 35° latitude this page gives 35° for a fixed mount, 20° in summer and 50° in winter for a seasonal setting, and 31.5° for the year-round rule. Real sites depend on shading, roof pitch and weather.
What is the seasonal tilt adjustment?: Subtract 15° from the latitude for the summer setting and add 15° for the winter setting, each kept between 0° and 90°. At 40° that is 25° and 55°. At 10° latitude the summer tilt is 0°, because 10 − 15 is below zero.
Which direction should the panels face?: True south in the Northern Hemisphere (azimuth 180°) and true north in the Southern (azimuth 0°). A compass points to magnetic north, so correct for the local magnetic declination before you set the direction.
Should I use the latitude or 0.9 × latitude?: Start from the latitude: it is the fixed tilt the Department of Energy gives for the highest annual output. The 0.9 × latitude figure is a simple approximation that lands a little lower, 36° instead of 40° at 40°N. This page found no published source that establishes it, so treat it as a variant to compare, not a better answer.
What angle should solar panels be at each month?: Latitude minus the sun’s declination in the middle of the month, so the panel faces the noon sun. At 40°N the page gives 61.3° in January, 42.8° in March, 16.9° in June, 38.2° in September and 63.1° in December. A fixed mount cannot follow this; use it to decide when an adjustable rack is worth moving.
Does the page estimate how much power I will get?: No. It has no weather, shading or yield model and shows no energy figure, so it cannot say how much a few degrees off the rule would cost.

Important limitations

Rules of thumb for orientation, not an optimized design. Within about 23° of the equator the noon sun passes to the pole side of overhead for part of the year, and the monthly table then says to face the pole: at 10°N it gives 13.1° facing true north in June. City latitudes are rounded to 0.1°. Shading, roof pitch, local weather and the installer’s design decide the real angle, and the azimuth is true, not magnetic. At latitude 0 the page gives a fixed tilt of 0° and an azimuth of 180°, although a flat panel has no preferred direction; near the equator the fixed rules give a tilt of only a few degrees. Latitude must be from −90 to 90.

Sources

Last reviewed: 2026-10-22

Choosing between the three tilt rules

All three answers are angles from the horizontal; they differ in how often you move the panel. Pick a city to fill in its latitude, or type your own. Tilt equal to latitude is the place to start for a roof or ground mount that never moves. Latitude minus 15° in summer and plus 15° in winter suits an adjustable rack you are willing to re-set twice a year, so the panel meets the high summer sun and the low winter sun more squarely. The third figure, 0.9 times latitude, is a slightly flatter fixed angle shown for comparison; this page found no published source that establishes it as better than the latitude rule. On a pitched roof the roof angle usually decides, and the page has no shading, weather or yield model.

The tilt rules and true south

With latitude φ taken as an absolute value: fixed tilt = φ; seasonal summer = φ − 15 and winter = φ + 15, each kept between 0° and 90°; year-round tilt = 0.9 × φ. Azimuth is 180° for a latitude of 0 or more and 0° below it, measured from true north. Worked example: at 40° latitude a fixed mount is 40°, the seasonal settings are 25° and 55°, and the year-round rule is 36°. Month by month: the second table uses tilt = φ − δ, with δ the mid-month solar declination 23.45° × sin(360/365 × (284 + n)) counted positive in your own summer, so the panel faces the noon sun: 16.9° in June and 63.1° in December at 40°N. Setting true south with a compass: a compass points to magnetic north, and the angle between magnetic and true north, the magnetic declination, depends on where you are. Subtract an east declination from the true bearing to get the compass bearing: where the declination is 10° east, true south is a compass bearing of 180 − 10 = 170°. A west declination is added instead.

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Solar Panel Tilt Angle Calculator

Use the Solar Panel Tilt Angle Calculator

All three rules at 40.0° latitude

Tilt for each month at 40.0° latitude

About the Solar Panel Tilt Angle Calculator

The three tilt rules by latitude (Northern Hemisphere)

Tilt for each month (Northern Hemisphere)

How to use this tool

Frequently asked questions

Choosing between the three tilt rules

The tilt rules and true south

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Glass Weight Estimator

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