Mortgage Calculator

Calculate your total monthly mortgage payment (PITI), loan balance payoff curve, and interactive amortization schedule. See exactly how much goes toward principal, interest, taxes, and insurance.

Mortgage Parameters

Live calculation
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$/yr
Total Monthly Payment (PITI)
$2,220/ month
Loan Amount$280,000

P&I Payment

$1,770/mo

Total Loan Interest

$357,125

Total Cost

$637,125

Monthly Payment Breakdown (PITI)

Principal, Interest, Property Taxes, Insurance & PMI

$2,220Total / Mo
Principal & Interest

$1,770

80% • Loan P&I

Property Taxes

$350

16% • Taxes

Home Insurance

$100

5% • Insurance

Loan Amortization Balance Curve

Watch your remaining balance decline while cumulative interest accumulates

Total Balance (with Interest)
Your Contributions
Year 30: $357,125
$0$151k$301k$457kYr 0Yr 5Yr 10Yr 15Yr 20Yr 25Yr 30
Initial + Deposits$280,000
Interest Accumulated$357,125
Total Net Worth$357,125

You will pay $357,125 in total interest over 30 years (128% of loan principal).

Making one extra monthly payment per year or rounding up to the nearest $100 can shave several years and tens of thousands in interest off your mortgage.

Understanding Your Total Monthly Housing Cost (PITI)

When purchasing residential real estate, your monthly mortgage commitment typically includes four main pillars, known collectively as PITI:

  • Principal: The portion of each monthly payment that directly pays down your loan balance and builds net equity in the property.
  • Interest: The lender's finance charge for borrowing the capital, calculated as a percentage of the remaining loan balance.
  • Property Taxes: Municipal or county ad valorem taxes assessed on your home's value, held in escrow by your servicer.
  • Homeowners Insurance & PMI: Hazard property insurance plus Private Mortgage Insurance (PMI) if your initial down payment is less than 20%.
1. Monthly Principal & Interest Payment Formula (Amortization)
Monthly P&I (M)=Principal (P) ×
r(1 + r)ⁿ(1 + r)ⁿ - 1

where r = monthly interest rate (Annual Rate ÷ 12), and n = total monthly payments (Years × 12).

2. Full Monthly Housing Commitment (PITI)
Total PITI=Monthly P&I +
Annual Property Tax12
+
Annual Insurance12
+ Monthly PMI
Step-by-Step Calculation Breakdown
Step 1: Determine Loan Amount & Period (Home $350k, 20% Down $70k, 6.5% Rate, 30 Years)
Principal (P) = $350,000 - $70,000 = $280,000 | Monthly rate (r) = 6.5% ÷ 12 = 0.0054167 | Payments (n) = 30 × 12 = 360
Step 2: Solve Principal & Interest Payment
P&I (M)=$280,000 ×
0.0054167 × (1.0054167)³⁶⁰(1.0054167)³⁶⁰ - 1
=$1,770 / month
Step 3: Combine Taxes & Insurance (Taxes $4,200/yr = $350/mo, Insurance $1,440/yr = $120/mo)
Total PITI=$1,770 (P&I) + $350 (Tax) + $120 (Ins)=$2,240 / month

Comparing 15-Year vs. 30-Year Fixed Mortgages

The choice of loan duration significantly impacts your monthly cash flow versus long-term net worth. Here is a direct side-by-side financial comparison on a $300,000 loan balance:

Metric30-Year Fixed (6.50% APR)15-Year Fixed (5.75% APR)Strategic Advantage
Monthly P&I Payment$1,896 / mo$2,491 / mo30-year saves $595/mo in immediate cash flow
Total Lifetime Interest$382,633$148,46015-year saves $234,173 in total interest
Equity Build SpeedSlow in first 10 yearsImmediate and rapidPrincipal exceeds interest in Year 1 on 15-yr

Frequently Asked Questions

How is my monthly mortgage payment calculated?
Your monthly mortgage payment is calculated using the loan amount, interest rate, and loan term. The standard formula is: M = P × [r(1+r)^n] / [(1+r)^n – 1], where M is the monthly payment, P is the principal, r is the monthly interest rate, and n is the number of payments.
What's the difference between interest rate and APR?
The interest rate is the cost of borrowing the principal loan amount. APR (Annual Percentage Rate) includes the interest rate plus other costs such as broker fees, discount points, and closing costs, expressed as a yearly rate.
Should I choose a 15-year or 30-year mortgage?
A 15-year mortgage has higher monthly payments but saves significantly on total interest paid over the life of the loan. A 30-year mortgage offers lower monthly payments, making it more affordable month-to-month, but you'll pay more interest overall.
What is PMI and when do I need to pay it?
Private Mortgage Insurance (PMI) is typically required when your down payment is less than 20% of the home's purchase price. PMI protects the lender if you default on the loan. It usually costs between 0.5% to 1% of the loan amount annually.
How does the down payment affect my mortgage?
A larger down payment reduces your loan amount, resulting in lower monthly payments and less interest paid over time. With 20% or more down, you avoid PMI, saving hundreds per month.
What is an amortization schedule?
An amortization schedule is a complete breakdown of each mortgage payment throughout the loan term, showing how much goes toward principal versus interest each year.

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