US Mortgage Calculator

How US Mortgage Payments Are Calculated

US mortgages use the standard amortization formula to calculate fixed monthly payments over the loan term. The formula ensures each payment covers both interest on the remaining balance and a portion of the principal. The standard formula is:

• M = Monthly principal and interest payment
• P = Loan principal (home price minus down payment)
• r = Monthly interest rate (annual rate / 12)
• n = Total number of payments (years × 12)

For example, if you purchase a $350,000 home with 20% down ($70,000), borrowing $280,000 at 6.75% for 30 years, the monthly interest rate is 6.75 / 12 / 100 = 0.005625 and there are 360 total payments. The monthly principal and interest payment works out to approximately $1,816.

Understanding PITI: Your True Monthly Cost

Your mortgage payment is more than just principal and interest. The total monthly housing cost — known as PITI — includes four components that together determine what you actually pay each month:

• Principal: The portion that reduces your outstanding loan balance. In early years, this is a small fraction of the total payment, but it grows over time as the interest portion decreases.
• Interest: The cost of borrowing money, calculated on the remaining balance each month. On a $280,000 loan at 6.75%, the first month's interest is $1,575 — that is 87% of the payment going to interest alone.
• Taxes: Property taxes vary significantly by location, from under 0.3% in Hawaii to over 2% in New Jersey and Illinois. The national average is approximately 1.1% of the home's assessed value per year.
• Insurance: Homeowner's insurance protects against damage, theft, and liability. Average annual premiums range from $1,200 to $3,000 depending on location, coverage, and home value. If your down payment is below 20%, PMI adds an additional 0.5% to 1.5% of the loan amount per year.

PMI: When You Need It and How to Remove It

Private Mortgage Insurance (PMI) is an additional cost that protects the lender — not you — in case of default. It applies when your down payment is less than 20% of the home's purchase price. PMI typically costs between 0.5% and 1.5% of the original loan amount per year, which is divided into monthly payments. On a $280,000 loan, PMI at 0.8% adds about $187 per month to your payment.

There are several ways to eliminate PMI. First, you can make a 20% or larger down payment to avoid PMI entirely. Second, you can request PMI cancellation once your loan-to-value ratio reaches 80% through regular payments or home value appreciation (you may need a new appraisal). Third, under the Homeowners Protection Act, your servicer must automatically terminate PMI when your LTV reaches 78% based on the original amortization schedule.

Worked Examples: Three Mortgage Scenarios

Scenario 1: Starter Home — $250,000

Home price: $250,000. Down payment: 10% ($25,000). Loan: $225,000. Rate: 7.0%. Term: 30 years.

• Monthly P&I: $1,497
• Property tax (1.1%): $229/month
• Insurance: $125/month
• PMI (0.8%): $150/month
• Total PITI: $2,001/month
• Total interest over loan life: $314,028

Scenario 2: Median Home — $400,000

Home price: $400,000. Down payment: 20% ($80,000). Loan: $320,000. Rate: 6.5%. Term: 30 years.

• Monthly P&I: $2,023
• Property tax (1.1%): $367/month
• Insurance: $150/month
• PMI: $0 (20% down)
• Total PITI: $2,540/month
• Total interest over loan life: $408,281

Scenario 3: Higher-End Home — $600,000

Home price: $600,000. Down payment: 25% ($150,000). Loan: $450,000. Rate: 6.25%. Term: 15 years.

• Monthly P&I: $3,858
• Property tax (1.1%): $550/month
• Insurance: $200/month
• PMI: $0 (25% down)
• Total PITI: $4,608/month
• Total interest over loan life: $244,384 — significantly less with a 15-year term

Average US Mortgage Rates (2024-2026)

Mortgage rates have fluctuated significantly over recent years. After historic lows near 3% in 2021, rates climbed above 7% in 2023-2024 following Federal Reserve rate hikes. As of 2025-2026, rates have moderated somewhat but remain elevated compared to the pandemic era. Here is a snapshot of average rates by loan type:

Tips to Get the Best Mortgage Rate

1. Improve Your Credit Score

Your credit score is the single biggest factor in the rate you receive. Borrowers with scores above 760 typically get the best rates. Before applying, pay down credit card balances, fix any errors on your credit report, and avoid opening new credit accounts. A score improvement from 680 to 740 can save 0.5% or more on your rate, translating to tens of thousands over the loan's life.

2. Shop Multiple Lenders

Rates vary significantly between lenders. Get quotes from at least 3-5 lenders including banks, credit unions, and online lenders. Multiple mortgage inquiries within a 14-45 day window count as a single inquiry on your credit report, so there is no penalty for rate shopping. Even a 0.25% difference can save $15,000-$25,000 over a 30-year loan.

3. Consider Buying Points

Discount points let you pay upfront to lower your interest rate. One point typically costs 1% of the loan amount and reduces your rate by about 0.25%. If you plan to stay in the home for more than 5-7 years, buying points usually pays off. On a $300,000 loan, one point costs $3,000 but saves about $45/month, breaking even in about 5.5 years.

4. Make a Larger Down Payment

A down payment of 20% or more eliminates PMI and often qualifies you for a better interest rate. If 20% is not feasible, aim for at least 10-15% to reduce PMI costs and show the lender you are a lower-risk borrower. Some programs like FHA loans allow as little as 3.5% down but come with mandatory mortgage insurance for the life of the loan.

5. Choose the Right Loan Term

A 15-year mortgage typically offers rates 0.5-1% lower than a 30-year mortgage. While monthly payments are higher, you save enormously on total interest. If the higher payment stretches your budget, a 30-year mortgage with occasional extra principal payments offers flexibility while still reducing interest costs.

Property Tax Rates by State

Property taxes vary dramatically by state and even by county. The national average effective property tax rate is approximately 1.1% of home value. States with the highest rates include New Jersey (2.23%), Illinois (2.08%), Connecticut (2.15%), and New Hampshire (1.93%). States with the lowest rates include Hawaii (0.28%), Alabama (0.41%), Colorado (0.51%), and Louisiana (0.55%). Always check your specific county's tax rate when budgeting, as rates can vary significantly even within a single state.

First-Time Homebuyer Programs

Several federal and state programs help first-time buyers. FHA loans require only 3.5% down with a minimum credit score of 580. VA loans offer zero down payment for eligible veterans and active military. USDA loans provide zero-down financing in eligible rural areas. Conventional 97 loans allow just 3% down. Many states also offer down payment assistance programs, closing cost grants, and tax credits for first-time buyers. Research programs specific to your state and locality to maximize your benefits.