Mortgage Calculator
Estimate your monthly home loan payment, total interest, and amortization schedule with our comprehensive mortgage calculator.
Equity Build-Up Over Time
Watch your remaining loan balance decrease over the years. Extra payments accelerate equity growth and save thousands in interest.
Understanding Your Mortgage Payment
Principal & Interest
The core of your mortgage. Principal reduces your loan balance while interest is the cost of borrowing. Early payments are mostly interest; later payments shift toward principal.
Property Taxes
Annual taxes assessed by your local government based on your property's value. These are typically collected monthly through an escrow account managed by your lender.
Home Insurance
Covers damage to your home from fire, weather, theft, and liability. Required by all mortgage lenders. Costs vary based on home value, location, and coverage level.
PMI & HOA
PMI protects the lender when you put less than 20% down. HOA fees cover shared community amenities. Both add to your monthly cost but can be eliminated or are optional.
Real-World Case Studies
See how different mortgage scenarios play out with real numbers. These case studies illustrate the impact of down payments, loan terms, and extra payments on your total cost.
Down Payment Comparison: 5% vs 10% vs 20%
See how different down payment amounts affect your monthly payment, total interest, and PMI costs. Based on a $400,000 home with a 30-year fixed rate at 6.5%.
| Factor | 5% Down $20,000 down | 10% Down $40,000 down | 20% DownBest $80,000 down |
|---|
PMI estimated at 0.75% annual rate for loans with less than 20% down. Actual PMI rates vary by credit score, loan type, and lender. 5-year total includes down payment, principal, interest, and PMI paid over the first 60 months.
How Mortgage Payments Work
A mortgage is likely the largest financial commitment most people ever make. Understanding how your payment is structured, how interest works, and how different factors like down payment, term, and rate affect your total cost can save you hundreds of thousands of dollars over the life of the loan.
The Amortization Formula
Your monthly payment is calculated using the standard amortization formula: M = P[r(1+r)^n] / [(1+r)^n - 1]. Here, P is the loan principal, r is the monthly interest rate (annual rate divided by 12), and n is the total number of monthly payments (term in years × 12). This formula ensures each payment is the same amount while gradually shifting more toward principal and less toward interest over time.
Our mortgage calculator handles this math instantly. Every time you adjust your loan amount, rate, or term, it recalculates your payment, total interest, and generates a complete amortization schedule.
Understanding PITI: The Four Parts of Your Payment
Your total monthly housing cost is often called PITI — an acronym for the four main components:
- Principal — The portion of your payment that reduces your loan balance. In the first year of a 30-year mortgage, only about 10-15% of your payment typically goes to principal.
- Interest — The cost of borrowing money from the lender. Interest rates vary based on market conditions, your credit score, loan type, and down payment size.
- Taxes — Property taxes assessed by your local government. These are typically collected monthly through an escrow account, even though they are technically not part of the loan itself.
- Insurance — Homeowners insurance protects against damage and liability. If your down payment is under 20%, you will also pay PMI (Private Mortgage Insurance) until you reach 20% equity.
How Extra Payments Save You Money
Extra payments are one of the most powerful tools for reducing your total mortgage cost. When you make an extra payment, the entire amount goes directly toward principal, not interest. This reduces your balance faster, which means future interest charges are calculated on a smaller amount.
Consider a $400,000 loan at 6.5% over 30 years. Adding just $100 per month extra saves about $52,000 in total interest and pays off the loan about 3.5 years early. Double that to $200 extra per month and you save $96,000 and pay off nearly 7 years early. Even small extra payments add up dramatically over time because of the compound interest working in reverse — you are saving interest on interest.
15-Year vs. 30-Year Mortgages: Which Is Better?
The two most common mortgage terms are 15-year and 30-year. A 30-year mortgage offers the lowest monthly payment but costs significantly more over the long run. A 15-year mortgage has higher monthly payments but saves you tens or hundreds of thousands in total interest and usually comes with a slightly lower interest rate.
For example, on a $400,000 loan at 6.5%, a 30-year term costs about $2,528/month and $510,000 in total interest. A 15-year term at 6.0% costs about $3,375/month but only $208,000 in total interest — a savings of over $300,000. The trade-off is the higher monthly payment. Many people choose a 30-year loan but make extra payments when they can, getting the flexibility of a low payment with the interest savings of faster payoff.
The Impact of Your Down Payment
Your down payment affects three things: your loan amount, your interest rate, and whether you pay PMI. A larger down payment reduces all three. Putting 20% down eliminates PMI entirely, which typically costs 0.3-1.5% of the loan amount per year. On a $400,000 home, that is $100-$500 per month in extra cost.
However, putting less down is not always worse. If you can earn a higher return on your money elsewhere (for example, through retirement accounts or other investments), the opportunity cost of a larger down payment might exceed the PMI savings. Run the numbers for your specific situation using our calculator to compare different down payment scenarios.
Fixed-Rate vs. Adjustable-Rate Mortgages
Fixed-rate mortgages maintain the same interest rate for the entire loan term. This means your principal and interest payment never changes, providing predictability and protection against rising rates. Most home buyers choose fixed-rate loans, especially when rates are relatively low.
Adjustable-rate mortgages (ARMs) start with a lower introductory rate that is fixed for a period (typically 5, 7, or 10 years) and then adjusts annually based on market rates. ARMs can be a good choice if you plan to sell or refinance before the rate adjusts, or if you expect rates to decrease. However, they carry risk: if rates rise significantly, your payment could increase substantially.
How to Use This Mortgage Calculator (5 Steps)
Follow this sequence to estimate your true monthly housing payment and total cost of borrowing.
Frequently Asked Questions
How much house can I afford?
A common guideline is the 28/36 rule: your total housing costs should not exceed 28% of gross monthly income, and total debt payments should stay under 36%. This includes mortgage principal and interest, property taxes, insurance, and HOA fees. Use our calculator to test different home prices against your budget, and remember to factor in closing costs (2-5% of purchase price) and ongoing maintenance (budget 1-2% of home value annually).
Should I put 20% down?
A 20% down payment eliminates the need for Private Mortgage Insurance (PMI), which typically adds $100-$300 per month. However, putting less down preserves cash for other investments, emergency funds, or home improvements. Consider your complete financial picture: if your investments earn more than the PMI cost, a smaller down payment may be strategically better. Many buyers find the sweet spot is putting enough down to comfortably afford monthly payments while maintaining 3-6 months of expenses in reserve.
Fixed vs. adjustable rate mortgage?
Fixed-rate mortgages lock in your interest rate for the entire loan term, providing predictable payments and protection against rate increases. ARMs start with a lower introductory rate that adjusts periodically (typically after 5, 7, or 10 years). Choose fixed if you plan to stay in the home long-term or prefer payment stability. Consider an ARM if you plan to sell or refinance within 5-7 years, or if current ARM rates are significantly lower than fixed rates and you can afford potential increases.
How do extra payments save me money?
Extra payments go directly toward your principal balance, reducing the amount of interest charged in future months. Since mortgage interest compounds daily, even small extra payments create significant savings over time. For example, adding $200/month to a $400,000 loan at 6.5% saves approximately $119,000 in interest and pays off the loan 6.5 years early. Use our calculator's extra payment feature to see exactly how much you could save with your specific numbers.
What is an amortization schedule?
An amortization schedule shows every payment over the life of your loan, breaking down how much goes to principal versus interest. In early years, most of your payment covers interest. Over time, the principal portion grows as your balance decreases. Our calculator provides both yearly summaries for a high-level view and month-by-month details for complete transparency. Understanding your amortization schedule helps you decide whether extra payments are worthwhile and how quickly you're building equity.
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References & Sources
- Consumer Financial Protection Bureau (CFPB) — Loan Estimate explainer and mortgage education resources.
- Freddie Mac — Primary Mortgage Market Survey (PMMS) providing weekly average mortgage rates.
- Investopedia — Amortization definition and financial education articles.
- National Association of Realtors (NAR) — Housing market data and home buyer statistics.
- Fannie Mae — Mortgage basics and comprehensive home buying education resources.
- U.S. Department of Housing and Urban Development (HUD) — Home buying guide and FHA loan information for first-time buyers.
Mortgage payment estimates assume a fixed-rate loan and do not include PMI, HOA dues, or special assessments. Your actual APR depends on credit score, down payment, loan term, and debt-to-income ratio. Always compare Loan Estimates from at least three lenders under the TRID disclosure rule before committing.