2026 ADU Loan Calculator

Cash-Out Refinance ADU Loan Calculator

A cash-out refinance replaces your existing mortgage with a larger one and hands you the difference as a lump sum to fund the ADU. It only makes sense when your existing rate is close to current market — otherwise the HELOC route is cheaper. Use the calculator to see the true all-in monthly payment.

Enter your project details

$50K$800K
20% ($50,000)

Loan amount: $200,000

Featured

Cash-Out Refi

Replaces your current mortgage

$1,642/mo
Est. APR7.75%
Term20 yr
Total interest$194,055

Combines existing mortgage + ADU cost into one new 30-year loan.

HELOC

Variable rate, interest-only draw option

$1,611/mo
Est. APR7.50%
Term20 yr
Total interest$186,685

Flexible line of credit. Only pay interest on what you draw.

Construction-Perm

Draws during build, converts to mortgage

$1,704/mo
Est. APR8.25%
Term20 yr
Total interest$208,992

Funds disbursed by milestone. Permanent loan activates at completion.

Rent-coverage estimate

Typical ADU rent in the National region runs about $1,800/mo. That covers roughly 110% of the featured Cash-Out Refi monthly payment shown above.

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ADU loan product comparison

ProductTypical rateTermBest for
HELOC7.5–10.5% variable10 draw + 20 repayHomeowners with 20%+ equity who want flexibility
Home Equity Loan7.3–10.3% fixed10–30 yrBorrowers who want a fixed monthly payment
Cash-Out Refi7.5–8.5% fixed30 yrCurrent mortgage rate already near market
Construction-Perm8.0–12.0%12–18 mo then 30 yrGround-up builds over $200K
DSCR8.5–12.0%30 yrInvestors qualifying on rent
RenoFi8.0–11.0%10–20 yrLimited current equity, new-build ADUs

Frequently asked questions

What is a cash-out refinance ADU loan?

A cash-out refinance is a financing product structured specifically around the cash-flow and appraisal profile of an ADU build. The calculator above shows how its monthly payment, rate, and term compare to a standard HELOC on the same build cost.

Who should use a cash-out refinance for their ADU?

Borrowers pick a cash-out refinance when its structure (draw schedule, rate lock, qualification basis, or post-construction appraisal) lines up with their project. Compare the payment side-by-side against a HELOC and cash-out refi to confirm it is actually the cheapest path.

What credit and equity do I need for a cash-out refinance?

Most ADU-specific loan products require a 680+ FICO and leave 15–20% home equity after the draw. DSCR loans are the exception — they qualify against projected ADU rent instead of personal income but tend to price 1.0–1.5% higher than a conventional HELOC.

Can I combine a cash-out refinance with a HELOC?

Sometimes. Stacking products is legal but requires explicit lender approval on both sides. Many homeowners instead use a HELOC for the first phase (plans, permits, site prep) and refinance into a single long-term product once the ADU is complete and appraised.

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