Mortgage Calculator
Estimate your full monthly mortgage payment — principal, interest, property taxes, homeowners insurance, PMI, and HOA — and see exactly how much of each payment goes to principal versus interest over the life of the loan. Defaults are reasonable starting points; change any input and the payment, total interest, payoff date, and amortization update immediately.
Output is for general illustration only and is not financial, investment, tax, or legal advice. Actual loan terms, taxes, insurance, and PMI rates depend on your lender, location, and credit profile. See our Terms.
How this calculator works
Your principal-and-interest payment is computed from the standard mortgage formula:
M = P × [r(1+r)n] / [(1+r)n − 1]
where P is the loan amount (home price minus down payment), r is the monthly interest rate (annual rate ÷ 12 ÷ 100), and n is the total number of monthly payments (years × 12). That equation has one unique solution — the fixed monthly payment that drives the balance to exactly zero on month n. For a deeper walk-through with worked numbers, see our article on how to calculate a mortgage payment.
Amortization is what happens once that fixed payment starts hitting the loan. Interest is charged on whatever balance is still outstanding, so in month one almost the entire payment goes to interest and only a sliver to principal. Each month the interest portion shrinks slightly and the principal portion grows. The amortization table below shows that crossover for every single month of the loan.
PITI stands for Principal, Interest, Taxes, and Insurance — the four components most lenders bundle into a single monthly bill via an escrow account. We add two more rows on top: PMI (private mortgage insurance, required by most lenders when the down payment is below 20%) and HOA dues if your home is in an association. The "Total monthly payment" line at the bottom is what actually leaves your bank account each month.
PMI on this calculator is auto-applied at 0.5% of the loan balance per year (a typical mid-range estimate) whenever the down payment is below 20%. In the amortization schedule, PMI is included only while the loan-to-value ratio is above 80% — once enough principal has been paid down, PMI drops off automatically, the same way it does on a real conforming loan.
Frequently asked questions
How is monthly mortgage payment calculated?
The principal-and-interest payment uses the formula M = P × [r(1+r)n] / [(1+r)n − 1], where P is the loan amount, r is the monthly rate (annual rate ÷ 12 ÷ 100), and n is the total number of monthly payments. The result is the fixed payment that pays the loan off in exactly n months.
What does PITI mean?
PITI is Principal, Interest, Taxes, and Insurance — the four parts of a typical mortgage bill. Principal pays down the loan balance; interest is the cost of borrowing; taxes are property taxes (often escrowed monthly); insurance is homeowners insurance. PMI and HOA dues aren't in the acronym but are commonly added to the monthly payment.
When do I have to pay PMI?
Private Mortgage Insurance is typically required on conventional loans whenever the down payment is below 20% of the home price (loan-to-value above 80%). PMI usually costs 0.3%–1.5% of the loan per year and is paid monthly. Federal law generally requires lenders to cancel PMI automatically once the LTV drops to 78% on the original amortization schedule.
Should I choose a 15-year or 30-year mortgage?
A 15-year loan has a higher monthly payment but a lower interest rate and far less total interest over the life of the loan. A 30-year loan keeps the monthly payment low and frees up cash for investing, retirement, or reserves. The right choice depends on your cash flow, job stability, and what you'd otherwise do with the monthly difference. Run both terms in the calculator above to see the tradeoff in dollars.
Can I save money by making extra principal payments?
Yes — typically a lot. On a 30-year mortgage, just one extra monthly payment per year often shortens the loan by four to five years and saves tens of thousands of dollars in interest. Every extra dollar of principal stops accruing interest from that point forward, so the savings compound over the remaining term.
What this calculator doesn't model
- ARM loans — this calculator assumes a fixed interest rate for the entire term. Adjustable-rate mortgages reset on a schedule and require a different model.
- Mortgage points — paying points up front to lower the rate isn't modeled. Run the calculator twice (with and without the discounted rate) and compare lifetime interest to evaluate.
- Tax deductions — mortgage interest may be deductible depending on your situation, which effectively lowers the cost. We don't model that — talk to a tax professional.
- Closing costs — origination fees, title insurance, and other closing costs aren't included in the loan amount here. Real lenders may roll some of these in.
- Tax and insurance escalation — property taxes and insurance premiums tend to rise over time. The schedule below holds them constant for simplicity.