How the construction loan draw calculator works
Enter the maximum loan commitment separately from the amount you expect to draw. The first advance occurs at the beginning of month one. Each additional advance has its own amount and month. An advance in month four of a twelve-month project earns nine months of interest in this model, including month four.
The four advances can share a month or appear out of chronological order; their timing still determines the interest total. Set an unused advance amount to zero and choose a month within the construction period. Total advances cannot exceed the entered commitment, and months must be whole numbers between one and the project end.
Interest-only payments during construction
This version assumes interest is paid in cash each month and principal remains outstanding until construction ends. Monthly interest equals the cumulative amount advanced multiplied by the nominal annual rate divided by twelve. Undrawn commitment does not earn interest. Peak monthly interest is reached once all entered advances have occurred.
A lender that finances interest from a reserve produces a different outstanding balance. Daily accrual, changing rates, mid-month advances, repayments, and inspection-dependent releases also require a more detailed schedule. Reconcile the modeled interest with the loan agreement rather than using the total as a lender payoff quote.
A staged construction interest example
Consider a $400,000 commitment at an entered 12% annual rate over twelve months, with $100,000 advanced in months one, four, seven, and ten. The advances remain outstanding for twelve, nine, six, and three modeled months. Their interest charges are $12,000, $9,000, $6,000, and $3,000, totaling $30,000.
If all $400,000 were advanced at the start instead, the same rate and period would produce $48,000 of interest. The $18,000 difference comes entirely from timing. These values demonstrate the arithmetic; they are not a current loan offer, typical construction duration, or prediction of a project’s actual release schedule.
Commitment fees and permanent loan payment
The entered origination percentage applies to the full commitment, not just the drawn balance. Add fixed cash-paid loan closing charges separately. A 1% fee on a $400,000 commitment is $4,000 even when the borrower ultimately draws less. Other closing charges of $2,000 bring fees to $6,000 and the example financing cost to $36,000.
The permanent payment uses total advanced principal, an entered fixed annual rate, and a separate amortization period with monthly payments. It is an illustrative principal-and-interest calculation, not an automatic conversion promise. It excludes financed fees, a new lender’s closing costs, taxes, insurance, and underwriting requirements. Compare the construction agreement and the proposed permanent loan separately.
Scope and methodology reviewed October 1, 2026
The CFPB describes construction loans as short-term financing commonly advanced in stages and explains that repayment or conversion depends on the lender. EstateCalc turns a user-entered simplified draw schedule into transparent interest arithmetic. The calculator does not determine whether a project qualifies for financing or how much a lender will release after an inspection.
Test delays by extending the construction period while keeping advance dates unchanged, then compare total interest and fees. Test a smaller final advance to see the unused commitment. Use the development calculator for project costs and profit, and LTV/LTC for financing ratios; construction interest alone is neither total project cost nor investment return.
Reviewed methodology and sources
The methodology is reviewed for the stated version. The result remains a scenario estimate and depends on the inputs and applicable rules.
Construction Loan Calculator FAQ
Is interest charged on the entire construction commitment?
The model charges interest only on entered advances. Its origination fee applies to the commitment. Check the lender agreement for unused-line fees or other charges.
When does an entered advance start earning interest?
Every advance is modeled at the beginning of its selected month, and that month counts as a full interest month. Mid-month daily accrual is outside this version.
Can the calculator capitalize construction interest?
No. Interest is paid in cash and never added to principal. An interest reserve or financed-interest agreement requires a different draw and balance schedule.
Does construction-to-permanent conversion happen automatically?
No. The displayed permanent payment is a separate illustration from your entered rate and amortization. Approval and conversion depend on the lender and agreement.
What happens when total draws exceed the loan limit?
The inputs are rejected instead of silently reducing an advance. Increase the commitment only if that amount reflects your actual financing scenario.
Continue the property analysis
Compare this result with adjacent metrics, keeping each formula’s income, expense, and financing scope consistent.