How Construction Loan Calculations Work
Construction loans differ significantly from traditional mortgages. Funds are disbursed in stages (draws) as construction milestones are met, and borrowers typically pay interest only on the amount drawn to date [citation:7][citation:10]. This calculator simulates that process to give you an accurate financial picture.
Key Formula: Monthly Interest Calculation
Monthly Interest = (Cumulative Drawn Amount × Annual Interest Rate) ÷ 12
Where:
- Cumulative Drawn Amount: The total loan funds released up to that point based on the draw schedule.
- Annual Interest Rate: The agreed-upon interest rate for the construction loan.
- Months: Each month of the construction period.
Example Calculation
For a $450,000 project with a 12-month construction period and a 6.5% interest rate:
- Month 1-2: 15% of funds drawn ($67,500). Monthly interest = ($67,500 × 6.5%) ÷ 12 = $366
- Month 3-5: Additional 25% drawn (total 40% = $180,000). Interest = ($180,000 × 6.5%) ÷ 12 = $975
- Month 6-8: Additional 30% drawn (total 70% = $315,000). Interest = ($315,000 × 6.5%) ÷ 12 = $1,706
- Final Months: 100% drawn. Interest = ($360,000 × 6.5%) ÷ 12 = $1,950
Note: These calculations are for estimation purposes. Actual loan terms, draw schedules, and interest calculations may vary by lender and specific loan agreement. Always consult with a financial professional for precise planning.
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Frequently Asked Questions
What is a draw schedule in a construction loan?
A draw schedule specifies key construction milestones that must be reached to trigger payment releases from the lender. Funding is typically released in 4-6 stages, from excavation to final completion, based on verified project progress [citation:7]. This ensures funds are used appropriately for construction purposes.
How is interest calculated during construction?
During construction, borrowers typically pay interest only on the funds that have been disbursed (drawn). As more funds are released according to the draw schedule, the monthly interest payment increases. This calculator accounts for this progressive interest accrual, which is a standard feature of construction loans.
What happens after construction is complete?
Once construction is finished and the project receives a certificate of occupancy, the construction loan is typically 'rolled' or converted into a traditional long-term mortgage. Payments then include both principal and interest, amortized over the selected term (e.g., 15, 20, or 30 years) [citation:7].
What is the typical loan-to-cost ratio for construction loans?
Most lenders finance 75-80% of the total project cost (land + construction). The borrower is typically required to provide a 20-25% down payment. This calculator automatically computes the Loan-to-Cost (LTC) ratio based on your inputs.