What a $300,000 Mortgage Actually Costs Each Month
Your monthly payment depends on three numbers: the loan amount, the interest rate, and how many years you have to pay it back
A $300,000 mortgage does not have one payment. The same loan amount costs you $1,432 per month at 3% interest over 30 years, but $1,899 per month at 6% interest over the same period. If you shorten the loan to 15 years at 6%, the payment jumps to $2,998. The difference between these scenarios is real money—hundreds of dollars every month for decades.
Your actual payment is built from principal (the amount you borrowed), interest (what the lender charges), property taxes (set by your county), homeowners insurance (required by your lender), and possibly mortgage insurance if you put down less than 20%. This section walks through how each piece works and what yours might look like.
Key Takeaways
- A $300,000 mortgage at 6% interest over 30 years costs approximately $1,799 per month in principal and interest alone—not including taxes, insurance, or mortgage insurance.
- Interest rates vary by lender, credit score, and market conditions, so comparing offers from at least three lenders can save you thousands over the life of the loan.
- Property taxes and homeowners insurance are added to your monthly payment and vary dramatically by location—a house in one county can cost $400 more per month than the same house in another.
- If you put down less than 20%, you will pay mortgage insurance (PMI) until you reach 20% equity, adding $150 to $300 per month depending on your down payment and credit score.
- Shortening the loan from 30 years to 15 years roughly doubles your monthly payment but cuts the total interest you pay nearly in half.
How principal and interest are calculated
The principal-and-interest portion of your payment is determined by a fixed formula. Lenders use an amortization schedule, which spreads your $300,000 debt across your loan term so that you pay the same amount every month. Early payments are mostly interest; later payments are mostly principal.
At a 6% interest rate over 30 years, your principal-and-interest payment is approximately $1,799 per month. At 5%, it drops to about $1,610. At 7%, it rises to about $1,996. A 1% difference in rate costs you roughly $190 per month on a $300,000 loan. Over 30 years, that 1% difference adds up to about $68,400 in total interest paid.
The interest rate you receive depends on your credit score, down payment size, loan term, the current market, and the lender you choose. Rates change daily. A borrower with a 760 credit score might receive 5.8%, while one with a 680 score might receive 6.5% for the same loan amount and term. Shopping with at least three lenders—a bank, a credit union, and a mortgage broker—takes a few hours and can reveal rate differences of 0.25% to 0.5%, which translates to $75 to $150 per month.
Property taxes and homeowners insurance add hundreds to your monthly bill
Your lender requires you to pay property taxes and homeowners insurance as part of your monthly mortgage payment. These are held in an escrow account and paid on your behalf. They are not optional, and they vary wildly by location.
Property taxes are set by your county or municipality and are based on your home's assessed value. In some counties, the effective tax rate is 0.5% of home value per year; in others, it is 1.5% or higher. On a $300,000 home, that means property taxes could range from $125 per month to $375 per month or more. A home in one county might have a $200 monthly tax bill while an identical home 20 miles away costs $400 per month. You cannot negotiate property taxes, but you can research them before you buy.
Homeowners insurance protects your lender's investment in the home. Rates depend on the home's age, location, construction type, and your claims history. A basic policy might cost $80 to $150 per month; a home in a flood zone or with an older roof might cost $200 to $300 per month. Get quotes from at least three insurers before closing.
Mortgage insurance (PMI) is a cost if your down payment is under 20%
If you put down less than 20% of the purchase price, your lender requires mortgage insurance. This protects the lender if you default, not you. On a $300,000 home with a 10% down payment ($30,000), you are borrowing $270,000, and mortgage insurance typically costs between 0.5% and 1.5% of the loan amount per year, depending on your credit score and down payment size.
That means mortgage insurance could add $112 to $337 per month to your payment. The cost decreases as your credit score rises and as your down payment increases. Once you reach 20% equity in the home (either through payments or home appreciation), you can request to have PMI removed. This usually takes 5 to 12 years, depending on your down payment and how quickly home values rise in your area.
Some borrowers choose to put down 15% and accept PMI rather than delay buying to save for 20%. Others refinance once they reach 20% equity to remove the insurance cost. Both are valid strategies; the right choice depends on your timeline and how confident you are in your income.
A sample breakdown of what $300,000 actually costs per month
| Component | Scenario A: 20% down, 6%, 30 years | Scenario B: 10% down, 6%, 30 years |
|---|---|---|
| Loan amount | $240,000 | $270,000 |
| Principal & interest | $1,439 | $1,619 |
| Property tax (example) | $250 | $250 |
| Homeowners insurance (example) | $120 | $120 |
| Mortgage insurance (PMI) | $0 | $202 |
| Total monthly payment | $1,809 | $2,191 |
These numbers are examples only. Your actual payment depends on your specific interest rate, property tax rate, insurance quotes, and down payment. Use these scenarios to understand the shape of the costs, not as predictions of your own bill.
The table shows how a smaller down payment increases your total monthly cost in two ways: a larger loan amount and the addition of PMI. In Scenario B, the extra $382 per month ($2,191 minus $1,809) reflects both the higher principal-and-interest payment and the mortgage insurance cost. Over 30 years, that difference totals more than $137,000.
How to compare loan offers and find the lowest total cost
When you receive loan offers from lenders, each one includes a Loan Estimate, a standardized form that shows your interest rate, monthly payment, closing costs, and total interest paid over the life of the loan. This form makes it easy to compare apples to apples.
Focus on three numbers: the interest rate, the annual percentage rate (APR), and the total interest paid over the loan term. The APR includes the interest rate plus lender fees, so it is a better comparison tool than the rate alone. A lender offering 5.9% with low fees might have a lower APR than one offering 5.8% with high fees.
Do not choose based on the lowest monthly payment alone. A 40-year loan has a lower monthly payment than a 30-year loan, but you pay far more interest overall. Similarly, a loan with a lower rate but higher closing costs might cost you more in the first five years than a loan with a slightly higher rate and lower upfront costs. The Loan Estimate shows you the total cost, so use it.
What changes your payment after you close
Your principal-and-interest payment never changes on a fixed-rate mortgage. However, your property taxes and homeowners insurance can increase. Lenders review your escrow account annually and adjust your payment if taxes or insurance have risen. A $50 increase in annual property taxes means a $4.17 increase in your monthly payment.
If you have an adjustable-rate mortgage (ARM), your interest rate can change after an initial fixed period, which means your principal-and-interest payment can rise or fall. ARMs are less common for 30-year mortgages but are sometimes offered at lower initial rates. Understand the terms before you sign: when the rate adjusts, how often, what the cap is, and what the worst-case scenario looks like.
Frequently Asked Questions
What is the difference between a 15-year and 30-year mortgage on $300,000?
At 6% interest, a 15-year mortgage costs approximately $2,998 per month in principal and interest, while a 30-year mortgage costs $1,799. Over the full term, the 15-year loan costs roughly $180,000 in total interest, while the 30-year loan costs about $347,000. The 15-year loan builds equity faster and costs less overall, but the monthly payment is nearly double.
Can I lower my monthly payment after I close?
You cannot lower your principal-and-interest payment on a fixed-rate mortgage without refinancing. Refinancing means taking out a new loan to pay off the old one, which involves new closing costs and a new appraisal. Refinancing makes sense if interest rates have dropped significantly (usually at least 0.5% lower) and you plan to stay in the home long enough to recoup the closing costs.
What happens if I pay extra toward principal each month?
Extra payments go directly toward principal and reduce the total interest you pay and the number of years until the loan is paid off. Paying an extra $100 per month on a $300,000 mortgage at 6% over 30 years can save you roughly $60,000 in interest and shorten the loan by about 5 years. Make sure your lender allows extra payments without penalty before you commit to this strategy.
How do I know if I can afford a $300,000 mortgage?
Most lenders use a debt-to-income ratio: your total monthly debt payments (including the new mortgage) should not exceed 43% of your gross monthly income. On a $300,000 mortgage with taxes and insurance, your total payment might be $2,000 to $2,500 per month. This means you would need a gross monthly income of roughly $4,650 to $5,800, or about $56,000 to $70,000 per year. Your actual approval depends on your credit score, savings, and employment history.
Should I get a lower interest rate or a larger down payment?
Both reduce your long-term cost, but they work differently. A larger down payment lowers your loan amount and eliminates PMI, saving you money immediately. A lower interest rate reduces your monthly payment and total interest over time. If you can negotiate a rate that is 0.5% lower, that often saves more money than putting down an extra 5%, especially over a 30-year term. Run the numbers with your specific situation before deciding.