How to Calculate Mortgage Payments (2026 Guide)
September 3, 2026 · 6 min read
Your mortgage payment is likely the largest monthly expense you will ever have. Understanding exactly how it is calculated — and what you can do to reduce it — can save you tens of thousands of dollars over the life of your loan. This guide breaks down the math, the variables, and the strategies that matter.
What Makes Up a Mortgage Payment
A typical mortgage payment has four components, often called PITI: Principal (the amount that reduces your loan balance), Interest (the cost of borrowing), Taxes (property tax, usually escrowed), and Insurance (homeowner's insurance and PMI if applicable). The principal and interest portion is fixed for a fixed-rate mortgage, while taxes and insurance may change annually.
How Interest Rate Affects Your Payment
| Rate | Monthly P&I | Total Interest (30yr) |
|---|---|---|
| 5.0% | $1,610 | $279,767 |
| 5.5% | $1,703 | $313,212 |
| 6.0% | $1,799 | $347,515 |
| 6.5% | $1,896 | $382,633 |
| 7.0% | $1,995 | $418,527 |
Based on a $300,000 loan over 30 years. A 2% difference in rate costs you nearly $140,000 in additional interest over the life of the loan. Shopping for the best rate is one of the most valuable things you can do.
30-Year vs. 15-Year Mortgage
A 15-year mortgage has higher monthly payments but saves you an enormous amount in interest. On a $300,000 loan at 6%, the 30-year option costs $1,799/month and $347,515 in total interest. The 15-year option costs $2,532/month but only $155,683 in total interest — a savings of nearly $192,000. If you can afford the higher payment, a shorter term is almost always the better financial decision.
The Impact of a Down Payment
A larger down payment reduces your loan amount, your monthly payment, and your total interest — and may eliminate the need for private mortgage insurance (PMI), which typically costs 0.5% to 1% of the loan amount per year. Putting 20% down instead of 5% on a $400,000 home means borrowing $320,000 instead of $380,000 and avoiding $1,900 to $3,800 per year in PMI.
How Extra Payments Save You Thousands
Adding even a small amount to your monthly payment can dramatically reduce your loan term and total interest. On a $300,000 loan at 6% over 30 years, adding just $200 per month to your payment would save you approximately $80,000 in interest and pay off the loan 7 years early. The extra payment goes entirely toward principal, which reduces the base on which future interest is calculated.
What to Check Before You Commit
Total cost of the loan — not just the monthly payment but the total amount you will pay over the full term. Break-even on points — if the lender offers to buy down your rate with points, calculate how many months it takes to recoup the upfront cost. Prepayment penalties — make sure your loan allows extra payments without fees. Escrow requirements — understand whether taxes and insurance are included in your quoted payment.
Calculate Your Mortgage
Use our free Mortgage Calculator to estimate your monthly payment, see the full amortization schedule, and understand how much you will pay in total interest.
Open Mortgage Calculator →Need to compare loan options? Our Loan Calculator handles any type of loan, and our Compound Interest Calculator shows how your savings grow over time.