ADU Loan Calculator for California Homeowners
Enter the loan amount, rate and term a lender quoted you to estimate a monthly payment on your California ADU. If the loan has an interest only phase during construction, switch it on to see the payment during the build and the payment after. It gives an estimate, not a quote.
- We explain every option, not just one product
- Matched with lenders who finance ADUs
- No obligation to take any offer
How to use the ADU loan calculator
Use numbers from a real quote or loan estimate, not an advertised rate.
Many California ADU construction loans charge interest only while the unit is being built, then switch to principal and interest. If yours does, turn on the interest only phase and enter how many months the lender expects it to last. For a HELOC, the interest only figure is a rough guide to the draw period once the full line is used.
At a glance
- What you need: a lender's quoted rate, term and amount
- What you get: principal and interest, plus the interest only payment
- What it leaves out: property tax, insurance, fees and rate changes
- Best used for: comparing two offers side by side
Estimate your ADU loan payment
Enter the figures from your quote. Change one at a time to see what moves the payment most: the rate, the term or the amount.
Your estimate
- Monthly principal and interest
- Interest only payment
This is an estimate, not a quote. Your lender sets the actual rate, payment and terms.
Before you trust the number
A payment only means something next to the budget it pays for. Check what drives California ADU cost, then compare how a construction loan and a HELOC charge interest during the build.
ADU cost in California
The cost lines that set your budget, and how to match them to a loan.
California ADU construction loans
Paid to your builder in draws as the unit passes inspection.
California HELOC for an ADU
Draw on your equity as builder invoices arrive.
ADU loan calculator questions
How long can you finance an ADU?
The lender and loan type set the term. A HELOC has a draw period followed by a repayment period. A construction loan has a short build phase, then converts or refinances into a permanent mortgage with its own term.
How to get money for ADU?
Most California owners use home equity, a construction or renovation loan, a refinance, or savings. Eligible owners can check whether the CalHFA ADU grant is open for early costs.
What type of loan is best for ADU?
There is no single best loan. Owners with strong equity and a low first mortgage rate often use a HELOC. Owners with less equity often need a loan that lends on the finished value.
Talk to a lender who finances ADUs
Want real numbers to put in the calculator? Tell us about your project and we will connect you with a lender who finances ADUs in California so you can compare actual quotes.
Thanks. We have your details and a lender who finances ADUs will be in touch, usually within one business day.