Mortgage Calculator: How Much Will Your Monthly Payment Be?

Your monthly mortgage payment is more than just paying back the loan. Lenders typically collect four components, known as PITI:

• Principal — the loan amount you're paying down
• Interest — the cost of borrowing
• Taxes — property taxes
• Insurance — homeowners insurance, plus PMI if applicable

Many homebuyers focus only on principal and interest and underestimate their true monthly cost by hundreds of dollars. Property taxes alone can add $200–$800/month, and if your down payment is under 20%, private mortgage insurance (PMI) adds 0.5–1.5% of the loan annually.

Your interest rate is the single biggest factor in your monthly payment. The impact of a 1% rate change is larger than most people intuit:

A move from 6.5% to 7.5% costs roughly $324,000 more in interest over the life of the loan. Fixed-rate mortgages lock your rate for the full term; adjustable-rate mortgages (ARMs) start lower but carry future risk.

In the early years, the vast majority of each payment goes to interest, not principal. On a 30-year fixed at 6.5%, roughly 80% of your first payment is interest. This gradually reverses — by year 20, about 60% goes to principal.

This is why extra payments early in the loan have outsized impact:

Every dollar of principal you pay down early is a dollar that stops accruing interest for the rest of the loan.

Private Mortgage Insurance (PMI) protects the lender if you default — borrowers with less than 20% down pay for it. PMI typically costs 0.5–1.5% of the loan amount per year.

On a $350,000 loan, that's $146–$438/month. The good news: it automatically terminates at 78% loan-to-value, or you can request cancellation at 80%.

FHA loans use MIP (Mortgage Insurance Premium) instead — an upfront fee plus annual premiums that usually last the life of the loan unless you put down 10%+.

Focusing only on the monthly payment hides the real cost. A $400,000 30-year mortgage at 6.5% results in roughly $510,000 of total interest — more than the loan itself.

This doesn't mean a mortgage is bad — real estate typically appreciates and mortgage interest is often tax-deductible. But understanding the lifetime cost changes decisions:

• A 15-year term roughly doubles your monthly payment but cuts total interest by 60%+
• Recasting after a lump-sum principal payment lowers your payment without refinancing
• Refinancing when rates drop 0.75–1%+ usually pays for itself within a few years

Before you start house hunting, know your all-in monthly number — principal, interest, taxes, insurance, and PMI — not just the loan payment. That's what determines whether the home fits your life.

The Mortgage Calculator on Adept.club includes every component of PITI, generates a full amortization schedule, and shows how extra payments change your total interest and payoff date. Free, no sign-up.