How Mortgages Work

Understanding the Loan That Pays for Your Home

A mortgage is a loan secured by real property. If you stop paying, the lender can take the house through foreclosure. That collateral is why mortgage rates are lower than credit card or personal loan rates. The lender has something valuable to repossess. Most homebuyers finance 80-96.5% of the purchase price, meaning you are borrowing hundreds of thousands of dollars. Understanding how that debt works, how interest accumulates, and where your monthly payment actually goes is not optional knowledge. It is the foundation of every financial decision you make as a homeowner.

Principal and Interest: Where Your Payment Goes

Every mortgage payment is split between two components. Principal is the portion that reduces what you owe. Interest is the cost of borrowing the money. On a $300,000 loan at 7% over 30 years, your monthly payment is $1,996. In month one, $1,750 of that payment goes to interest and only $246 goes toward principal. You read that correctly. In the first month, 87.7% of your payment is interest. By month 180 (halfway through the loan), the split is roughly even. By the final years, almost the entire payment goes to principal. This is called amortization, and it is why the early years of a mortgage feel like you are barely making progress on the balance.

See Your Amortization Schedule

Use this calculator to see exactly how your payments split between principal and interest over time. Enter your loan amount, interest rate, and term to generate a full amortization schedule. Watch how the principal portion grows each month while the interest portion shrinks. Making even small extra principal payments early in the loan can save you tens of thousands in interest.

Escrow: Taxes and Insurance in Your Payment

Your monthly mortgage payment is often more than just principal and interest. Most lenders require an escrow account that collects property taxes and homeowner's insurance as part of your monthly payment. The lender holds these funds and pays the bills on your behalf when they come due. On a $300,000 home with a $3,600 annual tax bill and $1,800 annual insurance premium, escrow adds $450/month to your payment. Your total monthly payment becomes $2,446 ($1,996 P&I + $450 escrow). You will often hear this called PITI: principal, interest, taxes, and insurance. PITI is your real monthly housing cost, and it is the number lenders use to calculate your debt-to-income ratio.

PMI: The Cost of Putting Less Than 20% Down

Private mortgage insurance (PMI) is required on conventional loans when your down payment is less than 20%. It protects the lender (not you) if you default. PMI costs 0.5-1.5% of the loan amount per year, depending on your credit score and down payment size. On a $285,000 loan (5% down on a $300K house), PMI at 0.8% costs $2,280 per year, or $190 per month on top of your PITI. PMI is not permanent. Once you reach 20% equity (either through paying down the mortgage or through home appreciation), you can request PMI removal. At 22% equity, the lender is required by law to cancel it automatically. The question for most buyers: is it worth waiting to save 20% down, or is it smarter to buy now with less and pay PMI while building equity? Run the numbers for your specific situation. In a market appreciating 4-5% per year, waiting two years to save a larger down payment can cost you more in missed appreciation than you save by avoiding PMI.

• PMI costs 0.5-1.5% of loan amount per year
• Required on conventional loans with less than 20% down
• Request removal at 80% LTV (20% equity)
• Automatic cancellation at 78% LTV (22% equity)
• FHA loans have their own version called MIP, which is harder to remove

Fixed Rate vs Adjustable Rate (ARM)

A fixed-rate mortgage locks your interest rate for the entire loan term. A 7% rate today is 7% in year 25. An adjustable-rate mortgage (ARM) starts with a lower rate for an initial period (typically 5 or 7 years), then adjusts annually based on a market index. A 5/1 ARM might start at 5.5% for the first 5 years, then adjust every year after that. The lower initial rate saves money early, but you take the risk that rates rise when the adjustment period begins. ARMs have caps that limit how much the rate can increase per adjustment (typically 2%) and over the life of the loan (typically 5-6%). A 5/1 ARM starting at 5.5% with a 5% lifetime cap could go as high as 10.5%. Compare a $300,000 loan over the first 7 years.

Loan Types: Conventional, FHA, VA, USDA

Not all mortgages are the same product. The loan type determines your down payment requirement, interest rate, mortgage insurance rules, and eligibility criteria. Most buyers qualify for at least two of these programs.