Mortgage calculator
Calculate your monthly mortgage payment (PITI) and total interest for a US home loan.
PITI = principal, interest, taxes and insurance. Excludes PMI and HOA fees.
How the calculation works
The principal & interest uses standard amortization: M = P·r / (1 − (1+r)⁻ⁿ), with r the monthly rate and n the months. Add property tax and insurance for PITI.
How much the rate changes your payment
For the default example ($320,000 loan, 30 years), the principal & interest payment by rate:
| APR | Payment (P&I) |
|---|---|
| 5.5% | $1,817 |
| 6.0% | $1,919 |
| 6.5% | $2,023 |
| 7.0% | $2,129 |
| 7.5% | $2,237 |
Half a percentage point moves the payment by ~$100/month — which is why shopping multiple lenders pays off.
15 vs 30 years
Same example at 6.5%: over 15 years the payment rises to ~$2,788, but total interest drops from ~$408k to ~$182k — less than half.
Examples
- $400,000 home with 20% down ($80,000), 30 years at 6.5%: P&I ≈ $2,023; PITI ≈ $2,514 with 1.1% tax and $1,500/yr insurance.
- Same home over 15 years: higher payment (~$2,788 P&I) but ~$226,000 less interest overall.
Frequently asked questions
What is PITI?
Principal, Interest, Taxes and Insurance — the full monthly housing cost.
What is PMI and when do I pay it?
Private Mortgage Insurance: usually required when the down payment is under 20%. It typically costs 0.3–1.5% of the loan per year and can be removed once you reach 20% equity.
How much house can I afford?
The 28/36 rule: housing costs (PITI) up to 28% of gross monthly income, and all debts combined up to 36%. On $8,000/month, that caps PITI at ~$2,240.
15-year or 30-year mortgage?
A 30-year has lower payments and more budget slack; a 15-year pays less than half the interest and builds equity faster. A common middle ground: take the 30-year and prepay when you can.
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Updated on July 2, 2026 · by Rafael Rossi · Methodology & sources