Rex says
The fast lane for the math you almost remember from school. Type the numbers, get the answer, move on with your day.
Try a scenario
Click to load — tweak from there.Inputs
Result
Year-round tilt (°)
35.3
Winter tilt (°)
52.0
Summer tilt (°)
22.0
Orientation
Face true south (north in S. hemisphere)
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter latitude (°).
- 2Read your year-round tilt (°) on the right — it updates as you type.
- 3Hit Share to keep the scenario or send it to someone.
About this calculator
A fixed array does best tilted near your latitude. Seasonal adjustments add roughly 15° in winter and subtract the same in summer.
Worked example
Using the values the calculator loads with:
Inputs
- Latitude: 37 °
Results
- Year-round tilt (°): 35.3
- Winter tilt (°): 52
- Summer tilt (°): 22
- Orientation: Face true south (north in S. hemisphere)
What each field means
Inputs
- Latitude (°)
- The latitude used in the calculation, measured in °. Starts at 37 ° so you have a working example on load. Accepted range: 0–70 °.
Results
- Year-round tilt (°)
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Winter tilt (°)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Summer tilt (°)
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Orientation
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the optimal solar panel tilt calculator work?
A fixed array does best tilted near your latitude. Seasonal adjustments add roughly 15° in winter and subtract the same in summer. The underlying maths is: Winter ≈ lat + 15°, summer ≈ lat − 15°, annual ≈ lat × 0.87 + 3.1
What do I need to enter?
Just one value: latitude. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the year-round tilt (°) result mean?
It is returned as a decimal number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Results are rounded for display; the underlying calculation keeps full precision.
Who is this tool for?
It's built for students, developers, and anyone who needs the answer right now without setting up a spreadsheet.
Accuracy and limitations
- Results are rounded for display; the underlying calculation keeps full precision.
- Very large or very small inputs may hit floating-point limits in the browser.
- Inputs outside the accepted range are clamped rather than rejected.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Solar Panel Tilt Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/roof-solar-tilt
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/roof-solar-tilt" target="_blank" rel="noopener">Solar Panel Tilt Calculator — RevenueLab</a> (2026).</p>
Source: [Solar Panel Tilt Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/roof-solar-tilt) (2026).