Solar Panel Tilt Angle Calculator
4 Solar Panel Angle Calculation Methods
Here are 4 different ways to calculate the optimal solar tilt angle for your location:
- Our Solar Panel Tilt Angle Calculator
- A Stanford Scientist's Tilt Angle Formula
- Simple Rules of Thumb
- An Excel or Google Sheets Spreadsheet
Let's run through each way, step-by-step.
1. Our Solar Panel Tilt Angle Calculator
Scroll up to our solar panel angle calculator at the top of this page.
In the box, enter a location such as your address, city, or zip code. Then select your location from the dropdown results or hit Enter.
Or you can just click "Use Your Current Location". (For this to work, make sure location services are enabled in your browser or in your phone's browser app.)
The calculator will calculate the optimal solar tilt angle for your location.
Note: The displayed tilt angle is the optimal year-round angle.
I live in Atlanta, GA.
To find my solar panel angle, I type in "Atlanta" into the calculator, then select "Atlanta, GA, USA" from the dropdown results.
My optimal year-round tilt angle is 28.6°.
2. A Stanford Scientist's Tilt Angle Formula
Our solar panel tilt calculator is based on a Stanford research paper.
The scientists behind it analyzed optimal solar tilt angles for all countries worldwide. Then, they produced two formulas to calculate the optimal tilt angle for any given location.
What are these magical formulas, you ask?
If you live in the northern hemisphere (latitude > 0):
Optimal tilt angle (northern hemisphere) = 1.3793 + Φ(1.2011 + Φ(-0.014404 + Φ0.000080509))
(Φ = latitude)
If you live in the southern hemisphere (latitude < 0):
Optimal tilt angle (southern hemisphere) = -0.41657 + Φ(1.4216 + Φ(0.024051 + Φ0.00021828))
(Φ = latitude)
There you have it:
A simple, research-backed way of calculating the optimal tilt angle of your solar panels.
Note: These are the formulas under the hood of our solar panel angle calculator at the top of the page.
Seasonal & Monthly Adjustments
The research paper doesn't provide a formula for how much to adjust your solar panel angle each month or season. So to figure that out, we'll use a rule of thumb:
Add 15 degrees in winter and subtract 15 degrees in summer if you live in the northern hemisphere (and the reverse for the southern hemisphere)
Optimum northern hemisphere tilt angles by season:
- Spring: Optimal tilt angle
- Summer: Optimal tilt angle - 15°
- Fall: Optimal tilt angle
- Winter: Optimal tilt angle + 15°
And if you wanted to adjust your solar panels every month, you could just adjust them by 5 degrees each month (bottoming out in June and maxing out in December in accordance with the summer and winter solstices).
Optimum northern hemisphere tilt angles by month:
- January: Optimal tilt angle + 10°
- February: Optimal tilt angle + 5°
- March: Optimal tilt angle
- April: Optimal tilt angle - 5°
- May: Optimal tilt angle - 10°
- June: Optimal tilt angle - 15°
- July: Optimal tilt angle - 10°
- August: Optimal tilt angle - 5°
- September: Optimal tilt angle
- October: Optimal tilt angle + 5°
- November: Optimal tilt angle + 10°
- December: Optimal tilt angle + 15°
I live in Atlanta, GA.
To find my latitude, I first go to Google Maps. Then I click on the map at or near my location.
Once I do, I see my location's latitude and longitude coordinates. The first number is my latitude.
According to Google Maps, my latitude is 33.7°.
Because my latitude is greater than 0, I can use the first formula listed above to calculate my best solar panel tilt angle:
My optimal year-round tilt angle = 1.3793 + Φ(1.2011 + Φ(-0.014404 + Φ0.000080509))
(Φ = latitude)
My latitude = 33.7°
My optimal year-round tilt angle = 1.3793 + (33.7°)(1.2011 + (33.7°)(-0.014404 + (33.7°)0.000080509))
After busting out my calculator (and doing a quick refresher on the order of operations), I get the following:
My optimal year-round tilt angle = 28.6°
If I want to adjust my solar panels seasonally or monthly, I can add and subtract based on the numbers laid out above.
Because our calculator uses these formulas, we came to the same answer as the first calculation method.
But we'll see that the remaining methods produce slightly different answers.
3. Simple Rules of Thumb
Don't wanna mess with the any solar tilt calculations?
Here are simple rules of thumb for finding your tilt angle:
Rule of Thumb: Your optimal solar tilt angle is equal to your latitude
Seasonal Adjustments: Subtract 15 degrees in the summer, add 15 degrees in the winter
Like I explained above, I used Google Maps to find my latitude.
Doing so, I learned that my latitude is 33.7°.
My optimal year-round tilt angle: 33.7°
My optimal tilt angles by season:
- Spring: 33.7°
- Summer: 18.7°
- Fall: 33.7°
- Winter: 48.7°
4. An Excel or Google Sheets Spreadsheet
Here's a simple spreadsheet for calculating the ideal angle for your solar panels:
How to save your own copy of the spreadsheet:
- Click the "View the Spreadsheet" button above
- If using Excel, File > Download > Microsoft Excel (.xlsx) to download your own copy
- If using Google Sheets, File > Make a copy > OK to save your own copy to your Google Drive
How to use the spreadsheet
- Enter your latitude. By default you'll see I've entered my own latitude, 33.7°.
- Locate your optimal year-round tilt angle. The spreadsheet includes a formula that will automatically calculate the optimal year-round tilt angle based on your location.
- Locate your optimal tilt angles by season and by month. These are seasonal and monthly adjustments based on the simple rules of thumb mentioned above.
Note: You do not need to send me a request for editing permission to use this spreadsheet. Just download it or make a copy following the instructions above.