Your payment depends on four things: the loan amount, the interest rate, the loan term, and your property taxes and insurance

The monthly payment you see on a mortgage statement is not just principal and interest. It includes four separate pieces: principal and interest (the amount you borrowed plus the cost of borrowing it), property taxes, homeowners insurance, and possibly mortgage insurance if you put down less than 20 percent. The first two are locked in when you close. The last two change based on where the property is and what happens to tax rates and insurance costs in your area.

A rough calculation: on a $300,000 loan at 7 percent interest over 30 years, principal and interest alone runs about $2,000 per month. Add $200 to $400 for property taxes (varies sharply by state and county), $100 to $200 for homeowners insurance, and possibly $150 to $300 for mortgage insurance if your down payment was under 20 percent. Your actual bill could land anywhere from $2,450 to $2,900 depending on location and your down payment size.

Key Takeaways

  • Principal and interest stay the same for the life of the loan, but property taxes and insurance can increase each year.
  • Property tax rates vary dramatically by state and county—a $300,000 home costs $2,400 per year in property tax in some places and $6,000 in others.
  • Mortgage insurance (PMI) is required if you put down less than 20 percent and typically costs 0.5 to 1.5 percent of the loan amount per year.
  • Your lender can give you a loan estimate within three days of process that shows the exact principal and interest payment, plus estimates for taxes and insurance.

How principal and interest are calculated

Principal and interest is the only part of your payment that follows a fixed formula. The lender divides the loan amount by the number of months, adjusts for the interest rate, and that number stays the same for 15, 20, or 30 years (or whatever term you chose). A $300,000 loan at 7 percent over 30 years costs $1,996 per month in principal and interest. A $300,000 loan at 6 percent over 30 years costs $1,799 per month. The difference between a 6 percent and 7 percent rate on that same loan is about $200 per month.

The term length matters just as much. That same $300,000 at 7 percent costs $1,996 per month over 30 years, but $2,797 per month over 15 years. You pay less interest overall with a 15-year loan, but your monthly payment is significantly higher. Most borrowers choose 30 years because the payment is lower, even though they pay more interest in total.

Property taxes: the part that changes every year

Property taxes are set by your county or municipality and are based on the assessed value of your home. They vary wildly by location. In New Jersey, the average effective property tax rate is around 0.8 percent of home value per year. In Texas, it is around 1.6 percent. In some rural counties, it can be lower; in some urban areas, it can be higher. On a $300,000 home, that means $2,400 per year in New Jersey or $4,800 per year in Texas.

Your lender will estimate property taxes based on the county rate and the purchase price, but the actual amount depends on the assessed value set by your local assessor after closing. Assessments can increase over time, which means your property tax bill—and your mortgage payment—can go up. Some states cap how much the assessment can increase in a single year; others do not. Ask your real estate agent or county assessor what the current rate is for the specific property you are buying.

Homeowners insurance and what it covers

Homeowners insurance protects the structure of your home and your belongings inside it. Your lender requires it as a condition of the loan and will include an estimate in your mortgage payment. The actual cost depends on the home's age, location, construction type, and the coverage limits you choose. A newer home in a low-crime area with good fire protection might cost $800 to $1,200 per year. An older home in a high-risk area could cost $1,500 to $2,500 per year or more.

Insurance costs have risen sharply in recent years in many states due to increased claims from weather events and inflation in repair costs. When you get a loan estimate from your lender, the insurance figure is an estimate only—your actual quote from an insurance company may be higher or lower. Shop with at least three insurers before closing to see what the real cost will be. If the actual insurance is higher than the lender's estimate, your monthly payment will be higher than the initial quote.

Mortgage insurance (PMI) and when you pay it

If you put down less than 20 percent, your lender requires private mortgage insurance (PMI). This protects the lender if you stop paying, not you. PMI typically costs 0.5 to 1.5 percent of the loan amount per year, depending on your credit score, the size of your down payment, and the lender's requirements. On a $300,000 loan with a 10 percent down payment ($30,000), PMI might cost $150 to $450 per month.

PMI is not permanent. Once you have paid down the loan to 80 percent of the original home value (or 78 percent in some cases), you can request that PMI be removed. If you put down 10 percent on a $300,000 home, you would need to pay the loan down to $240,000 before PMI drops off. Depending on your interest rate and how quickly you pay, this could take 8 to 12 years. Some borrowers refinance to remove PMI faster if interest rates drop or their home value increases.

How to get an accurate estimate before you commit

Your lender must provide a Loan Estimate within three business days of your process. This document shows the exact principal and interest payment, plus estimates for property taxes, insurance, HOA fees (if applicable), and PMI. The principal and interest figure is locked in and will not change. The tax and insurance estimates are based on the lender's research but may differ from your actual costs.

Before you sign a purchase agreement, get quotes from at least three homeowners insurance companies. This takes 15 minutes and gives you a real number instead of an estimate. Call your county assessor or ask your real estate agent for the current property tax rate in the area. If the property is in an HOA, ask for the annual HOA fee. Plug these real numbers into the lender's estimate to see what your actual payment will be. This is the only way to know before closing.

What happens to your payment after closing

Your principal and interest payment never changes. Property taxes and insurance almost always increase over time. Property taxes typically rise 2 to 4 percent per year as assessments increase or tax rates change. Insurance rates have been rising faster—sometimes 5 to 10 percent per year in states with high claim activity. Over a 30-year loan, these increases add up. A payment that starts at $2,500 per month might be $3,200 per month by year 15.

Your lender collects property taxes and insurance through an escrow account. Each month, you pay a portion into this account. When taxes or insurance bills come due, the lender pays them from the account. If the actual costs are higher than what you paid in, the lender will increase your monthly payment. If costs are lower, your payment may decrease slightly, though this is rare. You will receive an annual escrow statement showing what was paid and what your new payment will be.

Frequently Asked Questions

Can I lock in my interest rate before I find a home?

You can lock a rate for a short period (usually 30 to 60 days) after you have a purchase agreement, not before. Some lenders offer "rate locks" that extend to 120 days, but these cost extra. Until you have a signed contract and a property address, the lender cannot lock a rate because they do not yet know the loan amount or the exact risk.

What if property taxes or insurance go up after I close?

Your lender will adjust your monthly payment upward. You will see this on your annual escrow statement. If the increase is large, you can shop for a cheaper insurance company or appeal your property tax assessment (though appeals take time and are not always successful). You cannot avoid the increase, but you can sometimes reduce it.

Does a larger down payment lower my monthly payment?

Yes, in two ways. A larger down payment means you borrow less money, so principal and interest are lower. It also means you avoid PMI entirely if you put down 20 percent or more. On a $300,000 home, putting down 20 percent instead of 10 percent lowers your payment by roughly $300 to $400 per month.

Will my payment be the same for the entire 30 years?

Principal and interest will be the same. Property taxes and insurance will almost certainly increase. Over 30 years, these increases can add $500 to $1,000 per month to your payment. Budget for this by assuming your payment will be 20 to 30 percent higher in year 15 than it is at closing.

How do I know if my interest rate is good?

Compare rates from at least three lenders. Rates change daily and vary slightly between lenders based on their costs and risk assessment. A difference of 0.25 percent between lenders costs about $50 per month on a $300,000 loan. Shop around before locking a rate, and ask each lender for their Loan Estimate so you can compare the full cost, not just the interest rate.