Solar Tilt Angle Calculator

Find the optimal panel tilt angle for a latitude and season.

About Solar Tilt Angle Calculator

The optimal annual tilt is somewhat shallower than latitude because summer sun is stronger and lasts longer. Yield falls roughly with the square of the deviation, so being within ten degrees costs almost nothing. Because the penalty curve is flat near the optimum, matching an existing roof pitch is usually better than the cost and appearance of tilt frames.

Formula

Solar Tilt Angle

Annual optimal tilt ≈ 0.76 × latitude + 3.1 degrees

seasonal adjustment: About 15 degrees shallower for summer, steeper for winter

Worked example

With the default values below, Solar Tilt Angle Calculator returns Optimal Tilt Angle of 42.24. Change any input above and every figure here is recalculated in your browser.

Inputs used

Site latitudeaccepts -66–66 degrees: 51.5 degrees
Optimisation targetone of Annual yield, Summer, Winter: Annual yield
Current or proposed tiltaccepts 0–90 degrees: 30 degrees

Results

Optimal Tilt Angle: 42.24 degrees
Optimal Tilt for Annual Yield: 42.24 degrees
Difference From Your Proposed Tilt: -12.24 degrees
Estimated Yield Loss at Your Tilt: 0.524%
Guidance: Acceptable, with a small yield penalty

Step by step

1Values used
2Solar Tilt Angle
3Optimal Tilt Angle= 42.24 degrees
4Optimal Tilt for Annual Yield= 42.24 degrees
5Difference From Your Proposed Tilt= -12.24 degrees
6Estimated Yield Loss at Your Tilt= 0.524
7Guidance= Acceptable, with a small yield penalty

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Solar Tilt Angle calculated?

Annual optimal tilt ≈ 0.76 × latitude + 3.1 degrees The optimal annual tilt is somewhat shallower than latitude because summer sun is stronger and lasts longer. Yield falls roughly with the square of the deviation, so being within ten degrees costs almost nothing.

Why does Solar Tilt Angle matter?

Because the penalty curve is flat near the optimum, matching an existing roof pitch is usually better than the cost and appearance of tilt frames.

What values do I need to enter?

This calculator takes 3 inputs: Site latitude, Optimisation target, Current or proposed tilt. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.