Mortgage Basics: What Your Monthly Payment Really Includes

For most people a mortgage is the largest loan they’ll ever take. Understanding what makes up the monthly payment — and how it changes over time — turns a scary number into something you can actually plan around.

The four parts: PITI

Lenders sum up a mortgage payment with the acronym PITI:

• Principal — the portion that pays down what you borrowed.
• Interest— the lender’s charge for the loan.
• Taxes — property taxes, usually collected monthly into an escrow account.
• Insurance— homeowner’s insurance, also typically escrowed.

Our mortgage calculator shows the principal-and-interest portion; you add your local taxes and insurance on top. There may also be PMI (private mortgage insurance) if your down payment is under 20%, and HOA dues in some communities.

How amortization works

Your principal-and-interest payment stays the same every month on a fixed-rate loan, but its composition shifts dramatically. Early on, most of each payment is interest, because interest is charged on a large remaining balance. As the balance shrinks, more of each payment goes to principal. This is amortization.

The practical consequence: in the first years, you build equity slowly. A $400,000 30-year loan can have you paying mostly interest for the first decade. It’s also why extra principal payments early in the loan save so much — every dollar of principal you knock out now avoids years of interest on it.

15 vs 30 years

A shorter term means higher monthly payments but far less total interest, because you’re borrowing the money for half as long and usually at a lower rate. A 30-year loan keeps payments low and flexible but costs more over its life. Plug both terms into the mortgage calculator to see the trade-off in real numbers.

Rate vs. APR

The interest rate determines your payment; the APR bundles in certain loan fees to reflect the true yearly cost, making it the better number for comparing offers. A loan with a lower rate but high fees can have a higher APR than a competitor.

When refinancing makes sense

If rates fall meaningfully after you buy, refinancing can lower your payment — but it has closing costs. The key question is the break-even point: how long until the monthly savings recoup those costs. The refinance calculator answers exactly that.

Before you shop

Start with what you can comfortably afford, not the maximum you’ll be approved for. The home affordability calculator applies the 28/36 rule to find a sustainable price, and our house affordability guide walks through the costs buyers often forget.