How Mortgage Payments Work
Your monthly payment has two layers. First, amortized principal & interest from the loan formula. Second, escrow-style additions: PMI when your down payment is under 20%, plus monthly slices of property tax and homeowners insurance, plus HOA dues. Lenders call the full picture PITI, and PITI is the number that decides affordability, not P&I alone.
M = P·r(1+r)^n / ((1+r)^n − 1) + PMI + Tax/12 + Insurance/12 + HOA
P = Loan Amount, r = Monthly Rate, n = Total Months
Worked Example
Scenario: $450,000 home, $90,000 down, 6.5% / 30 years, $5,400 tax, $1,800 insurance
Principal & Interest
$2,275/mo
Total Monthly (PITI)
~$2,875/mo
Lifetime Interest
~$459,000
Down Payment
20%, no PMI
Drop the down payment to 10% and PMI (~0.5%/yr ≈ $150/mo) plus higher principal push the total past $3,200/mo, use the calculator to test your exact numbers.
What the Calculator Shows
- Total monthly payment, P&I plus PMI, tax, insurance and HOA in one number
- Principal & interest split, the amortized loan portion vs escrow costs
- PMI estimate, auto-added below 20% down so comparisons stay honest
- Lifetime interest, total P&I interest over the full term
- Payoff date, month and year of the final payment
Tips to Lower Your Payment
Compare 15 vs 30-year terms, shorter terms slash lifetime interest dramatically. Raising your down payment to 20% removes PMI entirely. Even 0.5% lower rate saves tens of thousands over 30 years, so test rate scenarios before locking. For the rent-or-own decision, pair this with our Rent vs Buy Calculator.