Solar Panel Angle Calculator
Choose a US city or enter latitude to draw the sun path and compare fixed, seasonal, and monthly panel-tilt starting points.
Enter your numbers
Changes calculate instantly and are written to this page’s URL.
Residential energy statement
Instant planning estimate · not a utility invoice
- Summer tilt
- 18.5°
- Spring / fall
- 33.5°
- Winter tilt
- 48.5°
- True-south azimuth
- 180°
- Jan monthly tilt
- 48.5°
- Feb monthly tilt
- 46.1°
- Mar monthly tilt
- 39.7°
- Apr monthly tilt
- 31.4°
- May monthly tilt
- 23.7°
- Jun monthly tilt
- 19.1°
- Jul monthly tilt
- 19.1°
- Aug monthly tilt
- 23.7°
- Sep monthly tilt
- 31.4°
- Oct monthly tilt
- 39.7°
- Nov monthly tilt
- 46.1°
- Dec monthly tilt
- 48.5°
How the solar panel angle calculator works
Panel tilt changes how directly sunlight reaches a module. This solar panel angle calculator uses latitude as a transparent first-pass rule and shows a fixed annual setting, three seasonal settings, and a smooth monthly schedule. Select a bundled city or enter latitude directly; no location request leaves the browser.
For US mid-latitudes from 25° to 50°, the fixed-angle rule uses 0.76 times latitude plus 3.1°. Below 25°, the flatter 0.87-times-latitude rule avoids an excessive tilt. Above 50°, the tool uses latitude itself as a conservative fixed setting.
Seasonal settings subtract 15° for summer and add 15° for winter, bounded between flat and vertical. Monthly values interpolate around the fixed angle; frequent adjustment adds labor and is often less valuable than an unshaded placement.
Azimuth is 180° for true south in the Northern Hemisphere. Magnetic compass south differs by local declination, and an east- or west-facing roof may still produce useful energy despite not matching the ideal orientation.
Worked example
At 40° north, the fixed rule gives 0.76 × 40 + 3.1 = 33.5°. The seasonal settings are 18.5° in summer, 33.5° in spring and fall, and 48.5° in winter.
How to read the result
Use these angles for planning racks, not structural design. A roof-mounted system normally follows the roof pitch because extra racking can add wind load and cost.
Planning inputs are deliberately editable because two homes in the same state can have different tariffs, roof conditions, equipment, and operating schedules. Save a scenario with “Copy link,” then change one assumption at a time. This makes the result useful for comparing decisions without implying false precision.
Common questions
What solar panel angle should I use by latitude?
Should panels face magnetic or true south?
Is a steeper winter tilt better?
Do I need to change tilt every month?
Sources
Formulas and defaults are documented in our data method. The principal references for this page are:
- NREL — PVWatts Calculator documentation (2025) — Production modeling, array orientation, and system-loss context.
- EIA — Electric Power Monthly, Table 5.6.A (2024 annual) — Residential electricity price benchmarks by state.
- U.S. Department of Energy — Homeowner’s Guide to the Federal Tax Credit for Solar Photovoltaics (accessed methodology, 2025) — Background only; 2026 eligibility is never assumed.