Construction Loan Calculator - Construction Loan Payment Calculator & Building Loan Calculator
Free construction loan calculator & building loan calculator. Calculate construction loan payments, interest during construction, and permanent loan conversion. Our calculator uses standard loan formulas to provide accurate analysis for construction financing decisions.
Last updated: October 19, 2025
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Total cost to build the structure
Optional: Down payment amount
Expected time to complete construction
Rate after construction converts to permanent mortgage
Total Project Cost
$250,000
Land + Construction
Construction Loan
$250,000
Construction Interest
$9,375
Monthly Payment (Construction)
$781.25
Interest-only
Permanent Loan Payment
$1,639.43
After construction
Permanent Loan Amount
$259,375
Total Interest Paid
$340,194
Construction Loan Analysis
- •Construction loans typically require interest-only payments during construction, converting to permanent mortgage upon completion.
Construction Loan Facts:
- • Construction loans are interest-only during construction phase
- • Interest accrues on drawn funds, not the full loan amount
- • Loans typically convert to permanent mortgage upon completion
- • Construction loans usually require 20-25% down payment or equity
Construction Loan Calculator Features
Payment Type
Interest-Only
Payments based on drawn funds during construction phase
Conversion
Construction to Permanent
Automatic conversion to permanent mortgage upon completion
Total Cost
Land + Construction
Comprehensive project cost breakdown and financing analysis
Method
On Drawn Funds
Interest accrues on funds actually drawn, not full loan amount
Equity
20-25% Typical
Option to include down payment in loan calculations
Guidance
Optimization Tips
Receive recommendations to optimize construction financing
Quick Example Result
For a $250,000 construction project with 12-month construction period:
Construction Loan
$250,000
Monthly Payment
~$780
Construction Interest
~$9,375
How Our Construction Loan Calculator Works
Our construction loan calculator uses standard loan formulas to calculate construction financing costs and payments. The calculation applies interest-only payment formulas during construction and permanent loan amortization formulas for post-construction payments.
Construction Loan Calculation Formulas
Total Project Cost = Land Cost + Construction CostConstruction Loan = Project Cost - Down PaymentConstruction Interest = Average Balance × Rate × MonthsMonthly Construction Payment = Average Balance × Monthly RatePermanent Loan = Construction Loan + Accrued InterestThese formulas provide accurate construction loan calculations. During construction, interest accrues on funds drawn (simplified as average balance). Upon completion, the construction loan plus interest converts to a permanent mortgage with standard amortization payments.
Shows construction phase interest-only payments and conversion to permanent mortgage
Understanding Construction Loans
Construction loans are specialized financing for building projects, different from traditional mortgages. They provide funds during construction and typically convert to permanent mortgages upon completion. Understanding construction loan mechanics helps plan financing, budget for interest costs, and make informed decisions about building projects.
- Construction loans are interest-only during construction phase (no principal payments)
- Funds are disbursed in draws as construction milestones are met
- Interest accrues only on funds actually drawn, not the full loan amount
- Construction-to-permanent loans automatically convert without refinancing
- Typical down payment requirements: 20-25% of total project cost
- Construction loan rates are typically 0.5-2% higher than traditional mortgages
Sources & References
- Consumer Financial Protection Bureau (CFPB) - Construction Loan InformationGuidance on construction loans, financing options, and consumer protections
- FDIC - Construction and Development LendingRegulatory information about construction loan requirements and practices
- HUD - FHA Construction LoansFederal Housing Administration construction loan programs and guidelines
Need help with other construction or mortgage calculations? Check out our Mortgage Comparison Calculator and Borrowing Power Calculator.
Get Custom Calculator for Your PlatformConstruction Loan Calculator Examples
Project Details:
- Land Cost: $50,000
- Construction Cost: $200,000
- Total Project: $250,000
- Construction Period: 12 months
- Construction Rate: 7.5%
- Permanent Rate: 6.5%
Calculation Steps:
- Construction Loan: $250,000 (project cost)
- Average Balance: $125,000 (simplified 50% of loan)
- Monthly Rate: 7.5% / 12 = 0.625%
- Monthly Payment: $125,000 × 0.625% = $781.25
- Construction Interest: $781.25 × 12 = $9,375
- Permanent Loan: $250,000 + $9,375 = $259,375
Result: $250,000 construction loan, $9,375 construction interest, $259,375 permanent loan amount
Monthly payment during construction: ~$781 (interest-only). Permanent loan payment calculated separately based on term.
With Down Payment Example
$250k project, $50k down payment
$200k construction loan, lower interest costs
Extended Construction Period
18-month construction timeline
Higher interest costs due to longer period
Frequently Asked Questions
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