Mortgage Calculator
Estimate your monthly mortgage payment, total interest, and full amortization schedule.
Your numbers
Monthly payment
$2,022.62principal & interest
- Principal & interest
- $2,022.62
- Property tax
- $300.00
- Home insurance
- $100.00
- PMI
- $0.00
- Monthly total
- $2,422.62
- Total interest
- $408,142.36
- Total of payments
- $728,142.36
Your monthly mortgage payment is more than principal and interest. Lenders bundle in property taxes, homeowners insurance, and — if your down payment is under 20% — private mortgage insurance (PMI). This guide breaks down each piece, shows the formula behind the principal-and-interest figure, and explains the levers that actually lower what you pay.
What makes up your monthly payment (PITI)
Lenders think in PITI:
- Principal — the portion that pays down what you borrowed.
- Interest — the lender's charge on the remaining balance.
- Taxes — annual property tax, collected monthly in escrow.
- Insurance — homeowners insurance, plus PMI if your equity is below 20%.
How the principal & interest payment is calculated
The core figure uses the standard amortization formula:
M = P · r · (1 + r)ⁿ ⁄ ((1 + r)ⁿ − 1)
where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the number of payments (years × 12).
On a $400,000 home with $80,000 down, you borrow $320,000. At 6.5% over 30 years, the principal & interest comes to about $2,022.62/month. Add $3,600/year in property tax ($300/mo) and $1,200/year insurance ($100/mo) and your real payment is $2,422.62 — the number the calculator above shows.
Principal vs. interest over time
Early in the loan, most of each payment is interest because the balance is large. As the balance falls, more goes to principal. On a 30-year loan at 6.5%, you pay roughly the loan amount again in total interest over its life — which is why the levers below matter so much.
How to lower your payment or total interest
- A bigger down payment shrinks the principal and can eliminate PMI at 20% equity.
- A shorter term (15 vs 30 years) raises the monthly payment but slashes total interest dramatically.
- A lower rate — even 0.5% — meaningfully cuts both the payment and lifetime interest; shop multiple lenders.
- Extra principal payments shorten the loan and save interest; even one extra payment a year helps.
- Drop PMI as soon as you hit 20% equity by requesting cancellation.
The bottom line
Your real payment is principal + interest + taxes + insurance (+ PMI) — budget for all of it, not just P&I. Use the calculator to test how price, down payment, rate, and term change the monthly cost, then focus on rate and term, the two biggest drivers of lifetime interest. Mortgage rates here are your inputs, not live quotes — always confirm current rates with lenders.
Frequently asked questions
How is my monthly mortgage payment calculated?
The principal & interest portion uses the amortization formula M = P·r·(1+r)ⁿ ⁄ ((1+r)ⁿ−1), where P is the loan amount, r is the monthly rate, and n is the number of payments. Property tax, insurance, and PMI are then added on top.
What does PITI mean?
PITI is the four parts of a typical mortgage payment: Principal, Interest, Taxes (property tax), and Insurance (homeowners, plus PMI if applicable). Lenders look at full PITI when deciding what you can afford.
How much interest will I pay over the life of the loan?
On a 30-year loan, total interest can approach or exceed the amount borrowed. For example, $320,000 at 6.5% over 30 years costs well over $400,000 in interest across the full term — which is why rate and term matter so much.
What is PMI and how do I avoid it?
Private mortgage insurance protects the lender when your down payment is under 20%. Avoid it by putting 20% down, and cancel it once you reach 20% equity by requesting removal from your lender.
Is a 15-year or 30-year mortgage better?
A 15-year loan has higher monthly payments but far less total interest and builds equity faster. A 30-year loan has lower, more flexible payments but costs much more over time. Use the calculator to compare both for your numbers.
How does the down payment affect my payment?
A larger down payment lowers the loan amount (and therefore the payment and total interest) and can eliminate PMI at 20%. Even a few extra percent down noticeably reduces your monthly cost.
How can I lower my mortgage payment?
Put more down, secure a lower rate (shop several lenders), choose a longer term for a lower monthly payment, remove PMI at 20% equity, or refinance if rates drop. Extra principal payments cut total interest even if the monthly payment stays the same.
Does this calculator use live mortgage rates?
No — by design, the interest rate is your input, not a live quote. This keeps the tool fast, private, and accurate to your situation. Always confirm current rates directly with lenders before deciding.