When my friend Sara got pre-approved for a house, she did the math on a basic loan calculator and felt great: “$1,800 a month, totally doable.” Then the lender sent the real estimate. $2,400. She thought there’d been a mistake.
There wasn’t. She’d just calculated one part of the payment and forgotten the other three.
A mortgage payment is usually four things bundled together, and lenders even have a tidy acronym for it: PITI — Principal, Interest, Taxes, and Insurance. If you only budget for the first two, you’ll be surprised every single month. So let’s break it down.
The four pieces of PITI
Principal is the chunk of your payment that actually reduces what you owe. Early in a 30-year loan this part is small; near the end it’s most of the payment.
Interest is what the lender charges to lend you the money. In the first years of a mortgage, this is the biggest slice — which is why a house feels like it’s barely getting “paid down” at the start.
Taxes means property tax, set by your local government and based on your home’s value. It doesn’t go to the lender — they collect it monthly and pay it on your behalf through an escrow account.
Insurance is homeowners insurance, often collected the same way. If your down payment is under 20%, you may also pay PMI (private mortgage insurance) on top.
Try it yourself in the Mortgage Calculator — it adds taxes and insurance to the loan payment so you see the real monthly number, not the fantasy one.
A real example: a $350,000 home
Say you buy a $350,000 home, put $70,000 down, and take a 30-year loan at 6.5%. Here’s roughly how it lands:
- Principal and interest: about $1,770/month
- Property tax (~$3,500/yr): about $290/month
- Home insurance (~$1,500/yr): about $125/month
- Total monthly payment: about $2,185
That gap between “$1,770” and “$2,185” is exactly the surprise Sara ran into. Over a year it’s more than $4,900 — real money you need in the budget.
Why the term matters more than people think
A 30-year loan gives you a smaller monthly payment, which is why most buyers choose it. But you pay interest for twice as long as a 15-year loan, so the total cost is much higher. A 15-year loan costs more per month but saves a fortune in interest overall.
There’s no universally “right” answer — it depends on whether your priority is a lower monthly payment or a lower lifetime cost. The U.S. Consumer Financial Protection Bureau has a useful, unbiased explainer at consumerfinance.gov, worth a read before you sign anything.
Don’t forget the costs that aren’t in the payment
Even PITI isn’t the whole story of owning a home. Budget room for HOA dues if your home is in an association, maintenance (a common rule of thumb is about 1% of the home’s value per year), and closing costs up front, often 2–5% of the loan. A mortgage calculator gives you the monthly payment; your real cost of owning is that plus these.
Frequently asked questions
Does a bigger down payment lower my monthly payment?
Yes — twice over. You borrow less (so principal and interest drop), and once you cross 20% down you usually avoid PMI too. Test different down payments in the Mortgage Calculator and watch the total move.
Why is most of my early payment going to interest?
Because interest is charged on the remaining balance, which is largest at the start. As the balance shrinks, more of each payment goes to principal. It flips gradually over the years.
Should I pay extra toward principal?
Often a smart move — extra principal payments shrink the balance faster and cut total interest. Just confirm your loan has no prepayment penalty first.
What’s escrow?
An account your lender uses to collect your taxes and insurance monthly, then pay those bills for you when they’re due. It’s why your payment can change year to year even on a fixed-rate loan.
The takeaway
Before you fall in love with a monthly number, make sure it’s the real number — principal, interest, taxes, and insurance, plus a little room for maintenance and HOA. Run your home price through the Mortgage Calculator, then sanity-check whether that total fits a 50/30/20 budget.
This is general educational information, not financial advice. Talk to a licensed lender or advisor about your specific situation.
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