Your mortgage payment depends on four things: the loan amount, the interest rate, the loan term, and whether you have an escrow account

The basic calculation is straightforward. Take your loan amount, multiply it by your interest rate, divide by the number of months you'll be paying, and adjust for the fact that you pay interest on a shrinking balance. Most people use a mortgage calculator instead of doing this by hand, but understanding what goes into the number helps you see where your money actually goes.

If you already have a mortgage, your lender sent you a document called a Loan Estimate before closing and a Closing Disclosure at closing. Both show your principal and interest payment separately from taxes, insurance, and HOA fees. If you're shopping for a mortgage, a Loan Estimate from each lender will show you what your payment would be under their terms.

The payment itself has two parts: what goes toward the loan (principal and interest) and what goes into an escrow account for taxes and insurance. The escrow part changes every year when your property taxes or insurance rates change. The principal and interest part stays the same for the life of a fixed-rate loan.

Key Takeaways

  • Your principal and interest payment is determined by the loan amount, interest rate, and loan term — a 30-year loan at 7% on $300,000 produces a different payment than a 15-year loan at the same rate.
  • Your actual monthly payment usually includes escrow — money held by your lender to pay property taxes and homeowners insurance when they're due.
  • A Loan Estimate from your lender shows the exact breakdown before you close, and your Closing Disclosure shows what you actually locked in.
  • Early in the loan, most of your payment goes to interest; later, most goes to principal — this is why paying extra principal early saves the most money.

The four numbers that determine your payment

Loan amount is what you borrowed after your down payment. If the house costs $400,000 and you put down $100,000, your loan amount is $300,000. A larger loan means a larger payment.

Interest rate is what the lender charges you to borrow the money. Rates vary by lender, by the day you lock in, and by the type of loan. A rate of 6% produces a lower payment than 7%, all else equal. Your rate depends partly on your credit score, partly on market conditions, and partly on the loan term you choose.

Loan term is how many years you have to pay it back. A 30-year mortgage spreads payments over 360 months; a 15-year mortgage spreads them over 180 months. A shorter term means higher monthly payments but less interest paid overall. A longer term means lower monthly payments but more interest paid overall.

Escrow is money your lender collects each month to pay your property taxes and homeowners insurance when they're due. This amount varies by location and by your home's value. In some states or loan types, escrow is optional; in others, it's required. Your lender estimates the escrow amount and adds it to your principal and interest payment to give you your total monthly payment.

How to find your exact payment if you have a mortgage

Look at your monthly mortgage statement. It shows the payment amount due and breaks it down into principal, interest, taxes, and insurance. If you can't find a recent statement, log into your lender's website or call the customer service number on your loan documents.

Your Closing Disclosure — the document you signed at closing — shows your initial principal and interest payment. This number never changes on a fixed-rate loan. However, your escrow portion (taxes and insurance) can change annually when your property tax bill or insurance premium changes. Your lender will send you an escrow analysis each year showing the new estimate.

If you want to see the math behind the number, use an online mortgage calculator. Enter your loan amount, interest rate, and loan term. The calculator will show you the principal and interest payment. Then add your estimated property taxes and insurance to see your full monthly payment.

How to estimate your payment before you buy

If you're shopping for a home, get a Loan Estimate from at least two lenders. This document shows the exact payment you'd have under their terms, broken down by principal, interest, taxes, insurance, and any other fees. Lenders must provide this within three business days of your application, and it's free.

To estimate on your own, you need three numbers: the loan amount you're considering, the interest rate you expect to get, and the loan term you want. Use an online calculator with these inputs. Then add your estimated property taxes (your real estate agent or the county assessor can tell you the rate) and homeowners insurance (get quotes from at least two insurers). This gives you a rough total monthly payment.

Remember that your interest rate depends on market conditions and your credit score. If you have a credit score below 620, you may not may have access to for a conventional loan at all. If your score is between 620 and 680, you'll pay a higher rate than someone with a score above 740. Check your credit report before you apply so you know what to expect.

Why your payment changes even though your rate doesn't

On a fixed-rate mortgage, your principal and interest payment stays the same for 15, 20, or 30 years. But your total monthly payment can still go up because of escrow changes. When your property taxes increase or your homeowners insurance premium rises, your lender adjusts your escrow payment upward.

Your lender performs an escrow analysis once a year, usually around the anniversary of your closing. They look at what they actually paid out for taxes and insurance and compare it to what they collected from you. If they undercollected, they raise your monthly payment. If they overcollected, they may lower it or credit you the difference.

Property taxes can increase by 1% to 3% per year depending on your state and county. Insurance premiums often increase annually as well. Over a 30-year loan, these escrow increases can add hundreds of dollars to your monthly payment, even though your principal and interest stays flat.

The difference between a 15-year and 30-year payment

A 15-year mortgage has a higher monthly payment but costs less in total interest. A 30-year mortgage has a lower monthly payment but costs more in total interest. The choice depends on your budget and your financial goals.

On a $300,000 loan at 7% interest, a 30-year mortgage produces a principal and interest payment of roughly $1,996 per month. A 15-year mortgage on the same loan at the same rate produces a payment of roughly $2,996 per month — about $1,000 more. Over the life of the loan, the 30-year borrower pays roughly $418,000 in interest; the 15-year borrower pays roughly $239,000 in interest.

Some borrowers choose a 30-year loan for the lower payment and then pay extra principal when they can. This gives them flexibility: they can make the minimum payment in a tight month, but they can also accelerate payoff when money is available. Others choose a 15-year loan for the discipline and the interest savings, accepting the higher payment as a fixed commitment.

What happens to your payment if you refinance

Refinancing means taking out a new loan to pay off your old one. Your new payment depends on the new loan amount, the new interest rate, and the new term you choose. If you refinance to a lower rate, your payment usually drops. If you refinance to a longer term, your payment drops even if the rate stays the same. If you refinance to a shorter term or a higher rate, your payment goes up.

When you refinance, you pay closing costs again — typically 2% to 5% of the new loan amount. These costs include appraisal, title search, lender fees, and attorney fees. A lower payment only saves you money if the monthly savings add up to more than the closing costs within a reasonable time frame, usually three to five years.

Your new Closing Disclosure will show your new payment and new term. Compare it to your current Closing Disclosure to see exactly how much your payment will change and how long it will take to break even on the refinance costs.

Frequently Asked Questions

What's the difference between my principal and interest payment and my total mortgage payment?

Principal and interest is what you pay toward the loan itself. Your total payment also includes escrow — money your lender collects for property taxes and homeowners insurance. On a $300,000 loan, your principal and interest might be $2,000, but your total payment might be $2,600 because of taxes and insurance.

Can I pay off my mortgage faster by paying extra principal?

Yes. Any payment you make above your required monthly amount goes directly to principal, reducing the balance and the total interest you'll pay. Paying an extra $100 or $200 per month early in the loan can save tens of thousands in interest over 30 years. Check your loan documents to make sure there's no prepayment penalty.

Why does my payment change every year if I have a fixed-rate mortgage?

Your principal and interest payment doesn't change, but your escrow portion does. When property taxes or insurance premiums increase, your lender raises your escrow payment to cover the higher costs. This is normal and happens to most borrowers.

How do I know if my interest rate is good?

Compare your rate to current market rates from at least two other lenders. Rates change daily and depend on loan type, term, and credit score. Your real estate agent or mortgage broker can tell you what rates are available for your situation. A rate that was good six months ago may not be good today.

What if I want to lower my monthly payment?

You can refinance to a longer term, refinance to a lower rate if rates have dropped, or make a larger down payment if you haven't closed yet. You can also pay down your principal balance, which lowers future interest and can reduce your escrow payment if your loan amount drops below a certain threshold.