Solar Panel Tilt Calculator
Free solar panel tilt calculator. Get the optimal angle for year-round, summer, or winter solar production based on your latitude.
Solar Panel Tilt Angle Calculator
Formula used
Year-round: Tilt ≈ Latitude × 0.76. Closer to the equator = flatter, closer to poles = steeper.
Summer-optimised: Tilt ≈ Latitude − 15°. Captures higher-angle summer sun.
Winter-optimised: Tilt ≈ Latitude + 15°. Captures lower-angle winter sun.
For latitudes < 15°, summer tilt is clamped to 0°.
How to use this calculator
Enter your latitude (look it up on Google Maps — right-click any spot to see coordinates) and pick whether you want to optimise for year-round average, summer, or winter production. The calculator returns the optimal tilt angle measured from horizontal (0° = flat, 90° = vertical).
Use the preset buttons for common US/UK/AU latitudes if you don’t know yours.
What tilt angle actually does
Solar panels produce the most power when sunlight hits them at a 90° angle. Because the sun’s elevation in the sky changes throughout the day and across seasons, no single fixed tilt is perfect — it’s a compromise.
A steeper tilt favours winter production (when the sun is low in the sky) and sheds snow. A flatter tilt favours summer production (when the sun is high overhead) and is easier to install.
For most grid-tied homeowners, the goal is maximum annual kWh, which the year-round formula optimises for.
The formula
The simplest accurate rule of thumb:
- Year-round optimal tilt ≈ Latitude × 0.76
- Summer optimal tilt ≈ Latitude − 15°
- Winter optimal tilt ≈ Latitude + 15°
The 0.76 factor (rather than tilt = latitude exactly) accounts for cloud cover, atmospheric scattering, and the fact that summer days are longer than winter days. It’s the closer-to-real-world output across most climates.
For latitudes very close to the equator (under about 15°), summer tilt is clamped to 0° because the formula would otherwise return a negative angle.
Tilt vs azimuth — different things
Tilt is the angle from horizontal (how steeply the panel leans up). Azimuth is the compass direction the panel faces (south in the Northern Hemisphere, north in the Southern).
This calculator focuses on tilt. Azimuth should be true south (in the N. Hemisphere) for maximum production. Pointing 30° east or west of true south costs you roughly 5%.
When the rule of thumb breaks down
The latitude formula assumes a clear-sky climate. Three situations call for adjustment:
- Heavy snow climates: add 5–10° to make panels self-clear.
- Hot climates: flatter tilt slightly increases summer self-cleaning by rain.
- Tracking systems: if your panels follow the sun on a single-axis or dual-axis tracker, this formula doesn’t apply — your tracker software handles it.
For grid-tied systems where utility-scale optimisation is in your installer’s hands, your roof pitch may force the answer. In that case, accept what you have and verify the production is within 5% of optimal — usually it is.