Introduction

Welcome to the ADU Loan Calculator! Accessory Dwelling Units (ADUs) are secondary housing units on residential properties, such as backyard cottages, garage apartments, or basement suites. They’re an excellent way to expand living space, generate rental income, or accommodate family members. Financing an ADU, however, requires careful planning. This free, easy-to-use calculator helps you estimate your monthly loan payments and total interest based on your inputs. Whether you’re a homeowner exploring options or a builder crunching numbers, this tool provides quick and accurate insights to support your decision-making process.

How to Use the Calculator

Follow these simple steps to calculate your ADU loan payments:

• Loan Amount: Enter the total amount you intend to borrow for your ADU project.
• Interest Rate: Input the annual interest rate provided by your lender (e.g., 5.5%).
• Loan Term: Specify the repayment period in years (e.g., 15 or 30).
• Estimated ADU Cost: Provide the projected cost of constructing your ADU.

Click the “Calculate” button to view your monthly payment, total interest, and more. All fields are required, and the calculator includes validation to ensure accurate results.

Calculator

Results

Monthly Payment: $

Total Interest Paid: $

Total Amount Paid: $

Frequently Asked Questions

What is an ADU?

An Accessory Dwelling Unit (ADU) is a smaller, independent residential unit located on the same lot as a primary home. Examples include granny flats, in-law suites, or detached cottages.

How do I find the best interest rate?

Compare offers from multiple lenders, check your credit score, and explore local ADU financing programs for competitive rates.

Can I use this calculator for other loans?

Yes! It works for any fixed-rate loan—just adjust the inputs to match your loan details.

What if my ADU cost exceeds the loan amount?

You may need additional funding or to scale back your project. This calculator helps you plan accordingly.

More Resources

Explore more tools on usaloancalc.com.

Learn more about ADU financing from HUD, a trusted government resource.