How to Calculate Your Monthly Mortgage Payment
A mortgage is a loan used to purchase real estate, where the property itself serves as collateral. Your monthly mortgage payment consists of four components known as PITI: Principal (the loan amount being repaid), Interest (the cost of borrowing), Taxes (property taxes), and Insurance (homeowner's insurance and potentially PMI).
The standard amortization formula calculates the monthly principal and interest payment: M = P × [r(1+r)n] / [(1+r)n − 1]. For a $280,000 loan at 6.5% over 30 years: r = 0.065/12 = 0.005417, n = 360 months, giving M = $1,770.49 per month in principal and interest alone.
Understanding Mortgage Amortization
Amortization is the process of spreading your loan payments over time. In the early years of a mortgage, the majority of each payment goes toward interest. For example, on a $280,000 loan at 6.5%, your first monthly payment of $1,770 breaks down to approximately $1,517 in interest and only $253 toward principal. By year 15, the split is roughly equal. In the final years, nearly the entire payment goes to principal.
Over the full 30-year term, you'll pay approximately $357,375 in total interest on a $280,000 loan at 6.5% — more than the original loan amount. This is why even small rate reductions matter significantly: the same loan at 5.5% saves over $67,000 in interest over the life of the loan.
How Your Down Payment Affects Your Mortgage
The down payment directly reduces your loan principal and monthly payment. On a $350,000 home:
- 20% down ($70,000): $280,000 loan, ~$1,770/mo P&I, no PMI required
- 10% down ($35,000): $315,000 loan, ~$1,991/mo P&I, plus ~$131/mo PMI
- 5% down ($17,500): $332,500 loan, ~$2,102/mo P&I, plus ~$138/mo PMI
- 3% down ($10,500): $339,500 loan, ~$2,146/mo P&I, plus ~$141/mo PMI
Private Mortgage Insurance (PMI) is required when your down payment is less than 20%. PMI typically costs 0.3% to 1.5% of the original loan amount annually. On a $315,000 loan, PMI at 0.5% adds $1,575/year ($131/month). PMI can be removed once you reach 20% equity through payments or home value appreciation.
15-Year vs 30-Year Mortgage: Which Is Better?
A 15-year mortgage offers lower interest rates (typically 0.5-0.75% less) and dramatically less total interest, but requires higher monthly payments. Comparison on a $280,000 loan:
- 30-year at 6.5%: $1,770/month, $357,375 total interest
- 15-year at 5.75%: $2,325/month, $138,481 total interest
- Savings with 15-year: $218,894 in interest (but $555/month higher payment)
Choose a 15-year mortgage if you can comfortably afford the higher payment. Choose 30 years if you need lower monthly payments or plan to invest the difference in higher-returning assets.
Current Mortgage Rates in 2025-2026
As of early 2026, average US mortgage rates are:
- 30-year fixed: 6.25% – 7.00%
- 15-year fixed: 5.50% – 6.25%
- 5/1 ARM: 5.75% – 6.50%
- FHA 30-year: 5.75% – 6.50%
Rates are influenced by the Federal Reserve's monetary policy, inflation, the bond market (10-year Treasury yield), and your personal credit score. A credit score of 740+ typically qualifies for the best rates. Improving your score by 40 points (e.g., from 680 to 720) can save 0.25-0.5% on your rate — potentially $30,000-$60,000 over the life of the loan.
Hidden Costs of Homeownership Beyond Your Mortgage
Your mortgage payment is only part of the monthly cost of owning a home. Budget for these additional expenses:
- Property taxes: Average 1.1% of home value nationally ($3,850/year on a $350,000 home), but ranges from 0.28% (Hawaii) to 2.49% (New Jersey)
- Homeowner's insurance: $1,500-$3,000/year depending on location and coverage
- HOA fees: $200-$500/month for condos and planned communities
- Maintenance & repairs: Budget 1-2% of home value annually ($3,500-$7,000)
- Utilities: $200-$400/month for electricity, gas, water, trash, and internet
Tips to Lower Your Mortgage Payment
- Improve your credit score before applying — pay down credit card balances below 30% utilization
- Shop multiple lenders — rates can vary 0.5% or more between lenders on the same day
- Buy mortgage points — paying 1% of the loan upfront typically reduces your rate by 0.25%
- Increase your down payment — every additional $10,000 down saves ~$63/month on a 6.5% loan
- Choose a shorter term — 15-year mortgages have lower rates and save hundreds of thousands in interest
- Make biweekly payments — making half your payment every two weeks results in 13 full payments per year instead of 12, paying off a 30-year mortgage in about 25 years
Frequently Asked Questions
How much house can I afford?
The standard guideline is the 28/36 rule: your mortgage payment (PITI) should not exceed 28% of your gross monthly income, and total debt payments should not exceed 36%. On a $6,000/month gross income, target a maximum PITI of $1,680. With current rates, this supports roughly a $250,000-$300,000 home depending on taxes and insurance.
What credit score do I need for a mortgage?
Minimum scores: FHA loans require 580+ (3.5% down) or 500-579 (10% down). Conventional loans typically require 620+. The best rates require 740+. Each 20-point increase in score can save 0.125-0.25% on your rate.
Should I pay off my mortgage early?
It depends on your interest rate and alternative investment returns. If your mortgage rate is 6.5%, paying it off early guarantees a 6.5% "return." If you could invest that money at 8-10% in the stock market, investing may be better mathematically — though the psychological benefit of being debt-free is valuable to many homeowners.
What is an escrow account?
An escrow account is managed by your lender to collect and pay property taxes and insurance on your behalf. Your monthly PITI payment includes these amounts, and the lender disburses them when due. This protects the lender's collateral and ensures these critical bills are always paid on time.