Free ADU and Granny Flat Planner: Backyard Cottage Layout in 3D

An ADU (accessory dwelling unit), also called a granny flat or backyard cottage, is a small second home on the same lot as your main house. This planner starts you with a lot that has a main house, a small cottage, a path, a driveway, a fence and trees. Move things around, measure the gaps and see the result in 3D. It is free and needs no account.

Open the ADU template

How to plan your ADU

Open the template and press Plan. Turn on Labels in the Tools menu to see sizes.
Draw your own lot with Face and the lawn tag, then add your main house with the building tag.
Add the ADU as a second building. Pick the roof type before you press Finish.
Use Measure to check the distance from the ADU to the fence and to the main house.
Press Build 3D and walk around it. Save a PNG to show your family or designer.

Typical ADU sizes

Type	Typical size
Studio	300 to 450 sq ft (28 to 42 m²)
1 bedroom	450 to 700 sq ft (42 to 65 m²)
2 bedrooms	700 to 1,000 sq ft (65 to 93 m²)

Rules to check first

Maximum size: many places limit ADUs, often somewhere between 800 and 1,200 sq ft.
Setbacks: the minimum distance from the fence line differs by city. In some places it can be as small as 4 ft (1.2 m).
Parking, utilities and height also vary. Ask your local planning office.

Planscaper is for visualization only. It is not a permit drawing. Always follow local rules and ask a professional.

Design tips

Give the ADU its own entrance and path so both homes keep their privacy. Place windows so they do not look straight into the main house or the neighbor's yard. Leave room for the utility lines that run from the main house.

FAQ

Can I plan a garage conversion?

Yes. Use the garage template, change the roof and add a path to it.

Does it show the inside?

Not yet. It shows the outside shape, roof, windows and door.

Tiny house planner · Garage plan · Garden planner · Material calculator