What goes into your monthly house payment
Your monthly house payment is made up of four parts, often called PITI: principal, interest, taxes, and insurance. Principal is the amount you borrowed; interest is what the lender charges you to borrow it. Property taxes and homeowners insurance are added on top, and if you put down less than 20 percent, mortgage insurance gets added too. The lender calculates all of this and tells you the total before you sign the loan documents.
The principal and interest portion stays the same every month for a fixed-rate mortgage (the most common type). Property taxes and insurance can change year to year, so your total payment may shift even though the loan part does not. If you have an adjustable-rate mortgage, the interest rate itself can change after an initial period, which means your payment will change too.
You can estimate your payment before you apply for a loan, or you can look at your loan documents if you already have one. Both routes require the same three numbers: the loan amount, the interest rate, and the number of years you have to pay it back.
Key Takeaways
- Your monthly payment includes principal and interest (which stay the same on a fixed-rate loan), plus property taxes and homeowners insurance (which can change).
- To estimate your payment, you need the loan amount, the interest rate, and the loan term in years.
- Lenders provide a loan estimate within three business days of your application, which shows your exact payment breakdown.
- Property taxes vary by location and are assessed by your county; homeowners insurance costs depend on the home's value and your location.
- If you put down less than 20 percent, mortgage insurance (PMI) is added to your payment until you reach 20 percent equity.
How to calculate principal and interest yourself
The formula for monthly principal and interest is straightforward if you have a calculator or a spreadsheet. Multiply the loan amount by the monthly interest rate (annual rate divided by 12), then divide by one minus the result of (1 + monthly rate) raised to the negative power of the total number of payments. This sounds more complicated than it is in practice.
For example: a $300,000 loan at 6.5 percent over 30 years. The monthly interest rate is 0.065 divided by 12, or 0.00542. The total number of payments is 30 times 12, or 360. Plug those into the formula and the monthly principal and interest comes to about $1,896. That is the amount that goes toward paying down the loan itself and the lender's fee.
Most people do not do this math by hand. Instead, use a mortgage calculator on your lender's website, on Bankrate, or on the Consumer Financial Protection Bureau website. Type in the loan amount, rate, and term, and the calculator gives you the principal and interest instantly. You can also change the numbers to see how a different rate or a shorter loan term would change your payment.
Finding property taxes and homeowners insurance costs
Property taxes are set by your county assessor and vary widely by location. A home worth $400,000 might have annual property taxes of $4,000 in one county and $8,000 in another. To find your property tax rate, search "[your county] property tax rate" or call your county assessor's office. They can tell you the rate and often can estimate your annual tax based on the home's value.
Homeowners insurance protects the structure of the home and your belongings inside. Costs depend on the home's age, location, the coverage amount you choose, and your claims history. Get quotes from at least three insurers before you buy. Most lenders require you to have insurance in place before closing, and they will ask you to provide a quote or a binder (a temporary insurance document) during the loan process.
Both property taxes and insurance are paid into an escrow account held by your lender. The lender collects one-twelfth of the annual amount each month as part of your payment, then pays the bills when they are due. If taxes or insurance rates go up, your monthly payment goes up too.
Understanding mortgage insurance (PMI)
Mortgage insurance protects the lender if you stop paying. It is required when you put down less than 20 percent of the home's purchase price. The cost is usually between 0.5 and 1.5 percent of the loan amount per year, divided into 12 monthly payments. On a $300,000 loan, that could be $125 to $375 per month.
Mortgage insurance is not the same as homeowners insurance. You cannot opt out of it if you are putting down less than 20 percent, and it does not protect you—it protects the lender. Once you have paid down the loan to 80 percent of the home's original value (or 78 percent on some loan types), you can request that the lender remove it. Some lenders remove it automatically when you reach that point.
If you are considering a down payment of 15 or 18 percent, ask your lender what the mortgage insurance cost would be. Sometimes a slightly larger down payment saves you more in insurance costs than the extra cash you put down.
Reading your loan estimate
When you apply for a mortgage, federal law requires the lender to send you a Loan Estimate within three business days. This document shows your exact monthly payment, broken down by principal and interest, property taxes, homeowners insurance, mortgage insurance (if applicable), and any other fees. It also shows the total amount you will pay over the life of the loan.
The Loan Estimate is not a final bill—rates and insurance quotes can change, and you may shop around with other lenders. But it gives you the real numbers for the loan you are considering. Compare the Loan Estimates from different lenders side by side. The interest rate is the biggest driver of your payment, but also check the origination fee, appraisal fee, and title insurance cost, which vary by lender.
Before closing, you will receive a Closing Disclosure, which is the final version of your loan terms. This is where you confirm that the interest rate, loan amount, and payment match what you agreed to. Read it carefully and ask questions if anything does not match the Loan Estimate.
How changes in interest rates affect your payment
Interest rate changes have the biggest impact on your monthly payment. A 1 percent difference in rate can change your payment by $200 to $300 per month on a $300,000 loan. If you are shopping for a mortgage, even a difference of 0.25 percent is worth paying attention to.
On a fixed-rate mortgage, your interest rate is locked in at closing and never changes, so your principal and interest payment stays the same for the entire 15, 20, or 30 years. On an adjustable-rate mortgage (ARM), the rate is fixed for an initial period (often 3, 5, 7, or 10 years), then adjusts annually or semi-annually based on market rates. When the rate adjusts up, your payment goes up. ARMs usually start with a lower rate than fixed mortgages, but the payment can increase significantly later.
If you are locked into a high interest rate and rates have dropped, you can refinance—take out a new loan to pay off the old one. Refinancing has closing costs, so it only makes sense if you will stay in the home long enough to recoup those costs through lower payments.
What happens if your payment changes
On a fixed-rate mortgage, your principal and interest payment never changes. However, your total payment can increase if property taxes go up or if your homeowners insurance premium increases. Some lenders review your escrow account annually and adjust your monthly payment to make sure enough is being collected to cover taxes and insurance when they are due.
If your lender sends you a notice that your payment is going up, read it carefully. It will show the new tax or insurance amount and explain why the change happened. If you disagree with the property tax amount, you can appeal to your county assessor. If you think your insurance premium is too high, get quotes from other insurers and switch if you find a better rate.
On an adjustable-rate mortgage, your payment can increase significantly when the rate adjusts. Your loan documents will tell you the maximum the rate can increase per adjustment period and over the life of the loan. If you have an ARM, set aside money during the fixed-rate period so you can absorb the payment increase when it comes.
Frequently Asked Questions
Can I pay off my mortgage faster by paying extra each month?
Yes. Any extra payment you make goes directly toward principal, which shortens the loan term and saves you interest. Check your loan documents to make sure there is no prepayment penalty, then contact your lender to confirm how to apply extra payments. Some lenders require you to specify that the extra amount goes to principal.
What is the difference between a 15-year and a 30-year mortgage?
A 15-year mortgage has a higher monthly payment but you pay off the loan in half the time and pay much less interest overall. A 30-year mortgage has a lower monthly payment but costs more in total interest. The choice depends on whether you can afford the higher payment and how long you plan to stay in the home.
Does my credit score affect my monthly payment?
Your credit score does not directly change the payment amount, but it affects the interest rate you are offered. A higher credit score usually qualifies you for a lower rate, which lowers your payment. A lower credit score may result in a higher rate and a higher payment.
What if I want to change my loan term after I have already closed?
You can refinance to a different loan term, but this means taking out a new loan and paying closing costs again. Refinancing makes sense only if the new rate is significantly lower or if you want to shorten the term enough to save more in interest than you pay in closing costs.
How do I know if my property tax assessment is correct?
Your county assessor sends you a notice of assessment, usually annually. If you think the value is too high, you can file an appeal with your county. The process and deadline vary by location, so contact your assessor's office for instructions.