ADU Cost Calculator

Estimate your total cost, including construction, permits, and utilities.

What you need to know about this estimate:

This estimate is approximate. The real cost varies based on factors like ADU type, construction method, location, finishes, permit challenges, land elevation (flat vs sloped), choice of a second floor, and for conversions, the condition of the existing foundation and framing.

I got my estimate, now what?

Getting an estimate is the first step. Next, you'll plan your ADU, covering financing, design, permits, and construction. Our team assists with financing and planning your ADU, guiding it to completion. Schedule a call with us to talk about your project.

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1. What does the ADU Cost Calculator provide? It estimates the total cost of your ADU project, including construction, permits, and utilities.

2. How accurate is the estimate? It's approximate. Real costs vary due to ADU type, construction method, location, finishes, permit challenges, land elevation, second floor addition, and for conversions, the existing foundation and framing condition.

3. What factors influence ADU costs? Costs are influenced by the type of ADU, construction methods, location, finishes, permit acquisition, site elevation, second floor inclusion, and the state of the existing structure for conversions.

4. What should I do after getting my estimate? Plan your ADU, covering financing, design, permits, and construction. Our team assists with financing and planning, ensuring project completion.

5. Can your team assist throughout the ADU process? Yes, we help with financing, planning, design, permits, and construction, guiding your project to completion.

6. How do I start my ADU project with you? Schedule a call to discuss your project. We'll guide you through each step.

7. What is a feasibility check, and why is it important? A feasibility check evaluates your project's potential, considering local regulations, land use, and site conditions. It's crucial to ensure your project is viable before investing in detailed plans.

8. How do I get architectural plans for my ADU? Our team collaborates with skilled architects to create detailed plans tailored to your needs, ensuring compliance with local codes and optimizing the use of your space.

9. Can you connect me with contractors for my ADU project? Yes, we have a network of trusted contractors experienced in ADU construction. We can connect you with the right professionals for your project, ensuring quality and reliability.

10. How long does the ADU construction process take? The timeline varies based on the project's complexity, permit processing times, and construction details. Once we understand your specific requirements, we can provide a more accurate timeline.

Ready to get your ADU plans & permits?

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Benefits of Using an ADU Cost Calculator

An ADU cost calculator offers several benefits, making it an indispensable tool for homeowners.

Informed Decision-Making

One of the primary benefits is informed decision-making. With a clear understanding of the costs involved, homeowners can make strategic choices about their ADU project. This includes selecting the right type of ADU, choosing suitable finishes, and setting a realistic budget.

Easy to Use

Our user-friendly calculator simplifies the process of estimating ADU costs, making it accessible to all homeowners.

Budget Planning and Financing

The ADU calculator provides a helpful estimate for homeowners to gauge the potential costs of their project. However, for precise budget planning and securing financing, it's essential to obtain accurate cost estimations. This is where Scheduling a free call with our GatherADU experts becomes invaluable. Our team can provide personalized insights and detailed assessments tailored to your specific project needs, ensuring that your ADU endeavor stays on track and within budgetary constraints.


Instead of manually calculating costs, our calculator does the work for you, saving you time and effort.

Obtaining Financing or Loans

Accurate cost estimates are crucial when seeking financing or loans. Lenders are more likely to approve loans when you present a detailed and realistic budget, enhancing your chances of securing the funds needed for your ADU project.

Avoiding Unexpected Costs

Unexpected costs can derail any project. Our calculator helps you anticipate all possible expenses, from permits to utility connections, so there are no surprises along the way.

How Homeowners Can Use the ADU Cost Calculator

  1. Enter Your Location: Choose your state or city to get region-specific cost estimates.
  2. Choose ADU Type: Select from options like detached, garage conversion, room conversion, etc.
  3. Input Size: Specify the square footage of your planned ADU.
  4. Select Finish Quality: Choose between basic, mid-range, and high-end finishes.

Tips for Cost-Efficient ADU Construction

Plan Ahead

Planning is crucial for cost-efficient construction. Take the time to research and gather all necessary information before starting your project. This includes understanding local zoning laws, obtaining permits, and choosing cost-effective materials.

Use Quality Materials Wisely

While it might be tempting to go for the cheapest options, using quality materials can save you money in the long run. Invest in durable, high-quality materials for critical areas like the foundation and roofing, but consider budget-friendly options for non-essential finishes.

Hire Experienced Professionals

Hiring experienced contractors and architects can make a big difference in the quality and cost of your ADU. Professionals with experience in ADU construction can help you avoid common mistakes and ensure the project stays on budget.

Understanding ADU Costs

Types of ADU Costs

When planning your ADU project, it's vital to consider three main types of costs:

1. Hard Costs: These are the tangible expenses directly related to construction. They include costs for labor, materials, framing, wiring, roofing, HVAC systems, fixtures, and plumbing. The material used and the complexity of the ADU design heavily influence these costs.

2. Soft Costs: These are the non-physical expenses necessary for project completion. Soft costs encompass municipality permit fees, engineering and architectural fees, consultation fees, and other professional services required for project approval. The amount can vary significantly depending on local regulations.

3. Contingency Costs: These funds are set aside to cover unexpected expenses that may arise during the construction process. A contingency budget typically ranges from 5-10% of the total project cost, providing a safety net for unforeseen events.

Breakdown of Soft Costs

Soft costs can be less obvious but are just as crucial:

ADU Cost Breakdown by Percentage

Understanding the various cost components of an ADU project is crucial for accurate budgeting. Here's a detailed breakdown:

Site Preparation



Building Construction

Design and Architecture

Boundary & Survey

Permits and Impact Fees

General Observations:

Range of ADU Costs by State:

Range of ADU Costs by Type:

ADU Costs Based on Size:

Closing Thoughts

Thinking about adding an ADU to your property? It's a big decision, but it comes with great benefits. Here's what you should do:

  1. Get a Professional Property Check: This helps you understand your property better and plan your budget more accurately.
  2. Use GatherADU's Guidance: Compare costs and explore options with GatherADU's experts advice. Reach out our GatherADU experts

By following these steps, you'll have a clearer idea of how much your ADU project might cost and how to make it work for you. Ready to get started? Try out our ADU cost calculator to see the numbers for yourself and make your project a reality.