ADU Loan Calculator: Estimate Your Monthly Payment
Enter the loan amount, rate and term a lender quoted you and see the monthly principal and interest. If your loan has an interest only construction phase, the calculator shows that payment too. Use it to compare quotes, not to replace one.
- We explain every option, not just one product
- Matched with lenders who finance ADUs
- No obligation to take any offer
How an ADU loan payment is worked out
Most ADU loans are amortized. Each monthly payment is the same, but the split changes over time. Early payments are mostly interest, because interest is charged on a large balance. As the balance falls, more of each payment goes to principal.
Three things set that payment: how much you borrow, the rate, and the term. A longer term lowers the monthly payment but adds more interest over the life of the loan. A higher rate raises both.
Construction loans often add a step. While the ADU is being built you may pay interest only on the money drawn so far, then switch to a full payment once the loan converts.
At a glance
- You enter: loan amount, quoted rate, term in years
- Optional: interest only construction phase and its length
- You get: monthly principal and interest
- Not included: taxes, insurance, HOA dues
How to read your result
The number shown is principal and interest only. Your real monthly cost will be higher once property taxes, homeowners insurance and any HOA dues are added, and an ADU can raise your tax bill and insurance premium.
If you turned on the construction phase, the interest only figure assumes the whole loan has been drawn. Early in the build you will owe less, because interest is charged only on what has been paid out.
Use the same inputs for every quote so the comparison is fair.
Fill in the loan amount, rate and term to see the payment.
- Monthly principal and interest
- Interest only payment for the first , the most it could be
This assumes the whole loan has been drawn. Draws start smaller, so early payments are lower.
This is an estimate, not a quote. Your lender sets the actual terms.
When another loan fits better
If the payment looks high, the rate is often the lever, so learn what moves ADU loan rates. If you want a fixed payment from day one, a home equity loan gives you one. If the construction phase is what worries you, read how ADU construction loans release money.
ADU loan rates
What moves the rate on an ADU loan and how to compare offers fairly.
Home equity loan for an ADU
One lump sum at a fixed rate, with your first mortgage left alone.
ADU construction loans
Paid to your builder in draws as the unit goes up, then converted or refinanced.
ADU loan calculator questions
How long can you finance an ADU?
That depends on the loan type and the lender. Mortgages and cash-out refinances usually run longer than home equity loans, and HELOCs have a draw period followed by a repayment period. Ask each lender which terms they offer.
Is buying an ADU a good investment?
It can be if the unit adds value or rent that covers its cost. Compare the payment with the rent you could realistically charge, after taxes, insurance and upkeep, before deciding.
Does the payment include property taxes and insurance?
No. The calculator shows principal and interest only. Ask your lender for the full monthly cost, including any escrow for taxes and insurance.
Talk to a lender who finances ADUs
A calculator can only work with the numbers you give it. Tell us about your project and we will connect you with a lender who finances ADUs and can quote real terms.
Talk to a specialist: (555) 555-0141
Thanks. We have your details and a lender who finances ADUs will be in touch, usually within one business day.