Ask Numlight
Ask in plain English. Every number comes from our tested calculators.
Educational only, not financial advice. Your question is processed by our AI provider; please don't include personal details.
Worked example
A $400,000 home with 20% down ($320,000 loan) at an example rate of 6.5% for 30 years:
| Loan amount | Home price − down payment | $320,000.00 |
|---|---|---|
| Monthly interest rate | Annual rate ÷ 12 | 0.5417% |
| Number of payments | Years × 12 | 360 |
| Principal & interest | L × r ÷ (1 − (1 + r)^−n) | $2,022.62 |
| Property tax | Home price × tax rate ÷ 12 | $366.67 |
| Home insurance | Annual premium ÷ 12 | $150.00 |
| PMI | Loan × PMI rate ÷ 12 (while LTV > 78%) | $0.00 |
| HOA | $0.00 | |
| Total monthly payment | $2,539.29 |
Over 30 years you'd pay $408,141 in interest. The example rate is for illustration only — enter the rate from your lender's Loan Estimate for your own numbers.
Assumptions
- Fixed interest rate for the full term.
- Property tax, insurance and HOA stay constant (in reality they usually rise over time).
- PMI applies only when the loan is over 80% of the home price, and stops once the balance reaches 78% of the original price.
- Extra payments go entirely to principal.
Frequently asked questions
How is a monthly mortgage payment calculated?+
The principal and interest part uses the standard amortization formula: M = L × r ÷ (1 − (1 + r)^−n), where L is the loan amount, r is the annual rate divided by 12, and n is the number of monthly payments. Property tax, homeowners insurance, PMI and HOA dues are then added on top.
What does PITI mean?+
PITI stands for Principal, Interest, Taxes and Insurance — the four parts of a typical monthly mortgage payment. Many lenders collect taxes and insurance through an escrow account as part of the same payment.
When does PMI go away?+
On conventional loans, the federal Homeowners Protection Act requires PMI to end automatically when your balance is scheduled to reach 78% of the home's original value, and you can ask to cancel it at 80% if you meet the lender's requirements. FHA mortgage insurance follows different rules.
Do extra payments really save money?+
Yes. Extra payments go straight to principal, so less interest accrues every month after. Enter an amount in “Extra monthly payment” to see exactly how much interest you'd save and how much sooner the loan is paid off.
Do you store my information?+
No. Every calculation runs in your browser. We don't ask for your name, email or any personal information.
Calculator version 1.0.0. Results are estimates for educational purposes and are not a loan offer or financial advice.