It's one of the most common shocks in home-buying. You run a mortgage calculator, see $2,100/month, feel great about it — then you get your first statement and it says $2,680. What happened?

The answer is that most quick calculators only show you principal and interest (P&I). Your actual monthly payment is almost always higher because of four additional costs that get bundled into what's called your PITI payment.

The Four Components of a Real Mortgage Payment

1. Principal & Interest (P&I)

This is the part the simple calculators show you. On a $400,000 loan at 7% for 30 years, P&I is $2,661/month. It's fixed and predictable for the life of the loan.

2. Property Tax

Property tax is collected monthly by your lender and held in an escrow account, then paid to your local government annually. The national average is around 1.1% of home value per year — but it varies enormously by location. In New Jersey it averages 2.2%; in Hawaii, just 0.3%.

On a $400,000 home at 1.2% annual tax: $4,800/year = $400/month added to your payment.

3. Homeowner's Insurance

Your lender requires proof of insurance, and they typically collect the premium monthly via escrow. The US average is around $1,200–$1,500/year — more in hurricane or flood-prone areas. That adds roughly $100–$125/month to your payment.

4. PMI — Private Mortgage Insurance

If you put down less than 20%, you pay PMI until you reach 20% equity. PMI typically costs 0.5–1.5% of the loan amount annually. On a $360,000 loan (10% down on a $400k home) at 1%: that's $3,600/year = $300/month.

PMI is purely insurance for the bank — you pay it, they benefit from it. It disappears once you hit 20% equity, so it's worth tracking actively.

5. HOA Fees (If Applicable)

Condos, townhouses, and many planned communities charge monthly HOA fees that can range from $100 to over $1,000. Your lender doesn't usually collect this through escrow — you pay it separately — but it absolutely affects affordability and should be in your budget from day one.

A Real-World Example

$400,000 home, 10% down ($40,000), 7% rate, 30-year term, in a typical US suburb:

  • Principal & Interest: $2,395/month
  • Property Tax (1.2%): $400/month
  • Homeowner's Insurance: $110/month
  • PMI (0.8%): $240/month
  • HOA ($250/month): $250/month
  • Total Monthly Payment: $3,395/month

That's $734/month more than P&I alone — and $1,295 more than the calculator told you if it only showed the bare minimum.

When Does PMI Go Away?

Legally, lenders must cancel PMI automatically once your loan balance reaches 78% of the original purchase price. But you can request cancellation as soon as you hit 80% equity — either through payments or appreciation. If your home value rises, get a new appraisal and make the request early. Eliminating $300/month in PMI is effectively a $3,600/year raise.

The Escrow Surprise

Many first-time buyers are caught off guard by escrow shortages. Your lender estimates your annual tax and insurance costs at the start of the year. If taxes are reassessed higher mid-year, your escrow account comes up short — and your lender increases your monthly payment to cover the gap. These adjustments typically happen once a year and can add $50–$200/month with little warning.

What to Do Before You Buy

Before committing to a price range, get real numbers for all five components. Call the county assessor's office for current tax rates. Get insurance quotes for homes in your target zip code. Calculate whether PMI applies and for how long. Factor in HOA disclosures for any community you're seriously considering.

The difference between a house that's affordable and one that stretches you too thin is often found in these line items — not in the principal and interest.