Solar Panel Planner
Free solar panel roof layout tool: mark your roof on Google Maps or a photo to estimate panel count and total capacity in kWp.
Your roof. Your layout.
Upload a photo or try the sample roof.
Start by uploading a photo or map.
In map mode PNG export saves module layout only without Google map imagery. Take a screenshot for map background. Unfreezing map resets scale and markings.
How to understand results?
The tool searches for a denser regular grid at the chosen angle and evaluates multiple row offsets. It does not guarantee theoretical absolute maximum.
Calculated from 2D top-down projection. Roof pitch, perspective distortion, and measurement tolerances affect real capacity. Shading, structural load limits, and mounting brackets are not modeled. Final design must be verified against actual roof measurements.
kWp represents total nameplate DC capacity; it is not an annual kWh energy generation forecast.
How to plan solar panel placement on a roof?
This layout planner helps estimate how many solar modules fit in a marked roof area based on scale, perimeter, obstacles, panel dimensions, and setbacks.
- Upload a photo or open and freeze top-down Google Maps satellite imagery.
- Mark a known reference segment and enter its real length in meters.
- Mark the roof boundary, chimneys, skylights, and keep-out zones.
- Enter panel manufacturer dimensions and wattage, set inter-panel gaps and edge margins.
- Click "Arrange modules", compare orientations and row angles, then export the layout.
Panel count and system capacity
Panel count is determined by geometric placement within the roof contour avoiding obstacles and margins. Simply dividing total roof area by single panel area gives an inaccurate overestimate.
Total rated power (kWp) = module count × module wattage (W) / 1000. For example, 20 panels at 450 W equal 9 kWp. The tool does not estimate annual energy production in kWh or financial payback.
Frequently Asked Questions
How to calculate how many solar panels fit on a roof?
Choose Google Maps or upload a roof photo, calibrate the scale using a known length, and outline the roof perimeter and obstacles. Enter module dimensions, wattage, and margins. The planner arranges modules and shows estimated panel count and total kWp capacity.
Is the solar layout planner free?
Yes. The tool is 100% free and runs in your browser without registration. Google Maps mode requires no personal API key.
Can I use a Google Maps link without uploading a photo?
Yes. Select Google Maps, paste a share link or embed code, zoom straight top-down onto the roof, and click "Freeze view". Then calibrate scale and mark the roof.
How to set the image or map scale?
Click both ends of a visible scale bar or a known building edge. Enter its real length in meters. Google Maps does not provide scale automatically; accurate scale is critical for correct panel counts.
How is total solar capacity (kWp) calculated?
Total rated power kWp = module count × single module wattage W / 1000. For example, 20 panels of 450 W equal 9 kWp. This represents nameplate capacity, not annual kWh electricity generated.
Is the result suitable for a final solar installation project?
The result is intended for preliminary planning. It uses 2D projection and finds an optimal regular layout; theoretical maximum is not guaranteed. Roof pitch, shading, structural load capacity, and racking systems must be verified by a certified installer.
Is the photo sent to a server and how to save the plan?
Uploaded photos are processed entirely inside your browser and never sent to a server. In photo mode you can download a PNG plan. In map mode, PNG export saves the panel schema without map tiles; take a screenshot to capture the map background.