Mortgage Calculator
Calculate your monthly mortgage payment including principal, interest, taxes, and insurance (PITI). See the full amortization schedule.
Calculation Inputs
Results computed instantly — your data never leaves your device.
Live Results
Real-TimeTotal Monthly Payment
$2,596.83
Principal & Interest
$2,096.83
Property Tax
$400
Insurance
$100
Total Interest Paid
$434,858.61
Total Cost
$754,858.61
How to Use the Mortgage Calculator
- 1
Enter the home price and down payment amount.
- 2
Enter the annual interest rate and loan term (commonly 15 or 30 years).
- 3
Optionally add property tax rate (annual % of home value), home insurance (annual $), and HOA fee (monthly $).
- 4
See your complete PITI breakdown and total cost over the life of the loan.
Formula & Mathematical Basis
Variable Key
LLoan amount = Home Price − Down Payment
rMonthly interest rate = Annual Rate ÷ 12 ÷ 100
nNumber of monthly payments = Loan term in years × 12
M_PIMonthly principal and interest payment
M_TaxMonthly property tax portion
M_InsMonthly home insurance portion
HOAMonthly homeowners association fee (if applicable)
📝 PMI (Private Mortgage Insurance) applies when down payment is under 20% of purchase price. PMI typically costs 0.5–1.5% of the loan annually, added to the monthly payment. This calculator does not include PMI — add it manually if applicable.
Step-by-Step Examples
First-time buyer — $400,000 home, 10% down
Scenario: $400,000 purchase, $40,000 down, 6.85% rate, 30-year term, 1.2% tax, $1,200/yr insurance.
- 1.Loan amount: $400,000 − $40,000 = $360,000.
- 2.Monthly rate: 6.85% ÷ 12 ÷ 100 = 0.005708.
- 3.M_PI ≈ $2,361/mo.
- 4.M_Tax = $400,000 × 0.012 ÷ 12 = $400/mo.
- 5.M_Ins = $1,200 ÷ 12 = $100/mo.
- 6.Total PITI = $2,361 + $400 + $100 = $2,861/mo.
- 7.Note: PMI (~$150/mo) would apply due to <20% down.
Practical Use Cases
- Determining how much house you can afford based on income
- Comparing 15-year vs 30-year mortgage costs
- Evaluating refinancing scenarios when interest rates drop
- Understanding the full cost of homeownership beyond the list price
- Calculating break-even point for paying points to lower interest rate
- Rental property cash-flow analysis for real estate investors
Common Pitfalls
- Omitting property taxes, insurance, and HOA from affordability calculations — PITI can be 30–50% higher than principal and interest alone.
- Not budgeting for PMI when putting less than 20% down.
- Assuming the listed interest rate equals the APR — compare APR across lenders for a fair comparison.
- Ignoring closing costs (2–5% of loan amount) that must be paid upfront.
- Underestimating ongoing maintenance costs — budget 1–2% of home value annually.
Frequently Asked Questions
What does PITI stand for?
PITI stands for Principal, Interest, Taxes, and Insurance — the four components of a complete monthly mortgage payment. Lenders use your PITI to determine if you can afford a mortgage.
How much down payment do I need?
Conventional loans typically require 20% down to avoid PMI (private mortgage insurance). FHA loans allow as little as 3.5% down. The calculator shows your payment at any down payment amount.
How is the monthly mortgage payment calculated?
The principal and interest portion uses the standard amortization formula. Property tax is your home value × tax rate ÷ 12. Insurance is your annual premium ÷ 12.
What is the 28% rule for mortgages?
The 28% rule says your monthly mortgage payment should not exceed 28% of your gross monthly income. Lenders also look at total debt (36% rule). Use the calculator to find a payment that fits within these guidelines.
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