Mortgage Calculator Guide 2026: PITI, Amortization & US Home Buying

Buying a home is the largest financial decision most Americans will ever make. With median home prices hovering around $412,000 nationally in 2026, understanding how mortgages work is essential before you sign on the dotted line. A mortgage calculator helps you break down the true cost of homeownership — not just the loan payment, but the full picture including taxes, insurance, and interest over decades. This guide explains PITI, amortization, fixed versus adjustable rates, and how to use our calculator to plan your home purchase with confidence.

What is a Mortgage?

A mortgage is a loan used to purchase real estate, where the property itself serves as collateral. If you fail to make payments, the lender can foreclose and sell the property to recover their money. Most US mortgages are 30-year fixed-rate loans, meaning you pay the same monthly amount for 30 years until the loan is fully paid off.

Key mortgage terms you need to know:

• Loan amount (principal): The total amount you borrow, which is the home price minus your down payment.
• Down payment: The upfront cash you pay, typically 3% to 20% of the purchase price.
• Interest rate: The annual cost of borrowing, expressed as a percentage. Rates in 2026 range from approximately 6.2% to 7.1% depending on credit score and loan type.
• Loan term: The length of time to repay the loan, most commonly 30 or 15 years.
• Closing costs: One-time fees paid at closing, typically 2% to 5% of the loan amount, covering appraisal, title insurance, origination fees, and more.

Your monthly mortgage payment is just one piece of the puzzle. To truly understand what you will pay each month, you need to understand PITI.

Understanding PITI

PITI is an acronym that stands for Principal, Interest, Taxes, and Insurance. These four components make up your total monthly housing payment. Lenders use PITI to determine your debt-to-income ratio, which affects how much house you can afford.

Principal

The principal is the portion of your payment that reduces your loan balance. In the early years of a 30-year mortgage, only a small fraction of each payment goes toward principal. For example, on a $350,000 loan at 6.5%, your first monthly payment of $2,212 allocates only about $315 to principal and $1,897 to interest. Over time, this ratio shifts as your balance decreases.

Interest

Interest is the lender's profit for letting you borrow money. It is calculated as a percentage of your remaining loan balance. A 0.5% difference in interest rate can cost you tens of thousands of dollars over the life of the loan. On a $400,000 loan, the difference between 6.0% and 6.5% is roughly $48,000 in total interest paid.

Taxes

Property taxes are assessed by your local government (county, city, school district) and are typically 0.5% to 2.5% of your home's assessed value annually. These are usually collected monthly through an escrow account managed by your lender. In high-tax states like New Jersey and Illinois, property taxes can exceed 2% of the home value. In states like Hawaii and Alabama, they are well under 1%.

Insurance

Homeowner's insurance (also called hazard insurance) protects your home against damage from fire, storms, theft, and liability claims. Lenders require insurance as a condition of the mortgage. Annual premiums typically range from $1,000 to $3,500 depending on location, coverage amount, and claims history. If you put less than 20% down, you will also pay Private Mortgage Insurance (PMI), which adds 0.3% to 1.5% of the loan amount annually.

PITI Worked Example

How Amortization Works

Amortization is the process of paying off a loan through regular fixed payments over time. Each payment is split between interest and principal according to a predictable schedule. Understanding amortization helps you see exactly where your money goes and how extra payments can save you thousands.

The Amortization Curve

In the first year of a 30-year mortgage at 6.5%, approximately 94% of each payment goes toward interest. By year 15, the split is roughly 65% interest and 35% principal. In the final years, nearly all of your payment reduces the loan balance. This front-loading of interest is why refinancing in the early years can be costly — you have already paid most of the interest.

How Extra Payments Help

Adding just $200 per month to a $320,000 mortgage at 6.5% saves you approximately $132,000 in interest and pays off the loan about 7 years early. A single extra payment per year can shave 4 to 6 years off your mortgage. The power of amortization means any extra principal payment early in the loan has an outsized impact because it reduces the balance on which future interest is calculated.

Fixed-Rate vs Adjustable-Rate Mortgages

Choosing between a fixed-rate and adjustable-rate mortgage depends on how long you plan to stay in the home and your tolerance for payment uncertainty.

Fixed-Rate Mortgage (FRM)

• Interest rate stays the same for the entire loan term
• Monthly principal and interest payments never change
• Most common: 30-year and 15-year fixed
• Best for: buyers who plan to stay long-term and want payment predictability
• In 2026, 30-year fixed rates average around 6.5% and 15-year fixed around 5.7%

Adjustable-Rate Mortgage (ARM)

• Initial fixed rate for a set period (typically 5, 7, or 10 years)
• After the fixed period, rate adjusts annually based on a market index
• Common ARM types: 5/1, 7/1, 10/1 (first number = years fixed, second = adjustment frequency)
• Initial rate is typically 0.5% to 1% lower than comparable fixed rates
• Risk: payments can increase significantly if rates rise after the fixed period
• Best for: buyers who plan to sell or refinance within the fixed-rate period

Which Should You Choose?

If you plan to stay in your home for more than 7 years, a fixed-rate mortgage provides safety and predictability. If you expect to move or refinance within 5 to 7 years, an ARM can save you money with a lower initial rate. Consider your job stability, life plans, and whether you can afford a higher payment if rates rise when making this decision.

2026 US Mortgage Rates

Mortgage rates in 2026 have stabilized after the volatility of 2023-2025. The Federal Reserve's monetary policy, inflation trends, and economic growth all influence mortgage rates. Here is the current rate environment:

Loan Type	Average Rate (2026)	Typical Term
30-Year Fixed	6.4% – 6.8%	360 months
15-Year Fixed	5.6% – 6.0%	180 months
5/1 ARM	5.9% – 6.3%	360 months (5yr fixed)
7/1 ARM	6.1% – 6.5%	360 months (7yr fixed)
FHA 30-Year	6.0% – 6.4%	360 months
VA 30-Year	5.8% – 6.2%	360 months

FHA loans are insured by the Federal Housing Administration and allow down payments as low as 3.5% with credit scores of 580+. They carry mandatory mortgage insurance premiums for the life of the loan. VA loans are available to eligible veterans and active military with no down payment required and no PMI, though a VA funding fee applies.

How to Use the Mortgage Calculator

Our mortgage calculator gives you a complete picture of your monthly housing cost and total interest paid over the life of the loan. Here is how to get the most out of it:

1. Enter the home price — the total purchase price of the property you are considering.
2. Input your down payment — as a dollar amount or percentage. Try different scenarios to see how PMI affects your payment.
3. Select your interest rate — use the current average for your loan type, or input your pre-approval rate.
4. Choose your loan term — 30-year for lower payments or 15-year for faster payoff and less interest.
5. Add property taxes and insurance — estimate based on local tax rates and insurance quotes for an accurate PITI figure.
6. Review the amortization schedule — see how each payment splits between principal and interest over the full loan term.

The calculator shows your monthly PITI payment, total interest paid, payoff date, and a visual amortization chart. Run multiple scenarios — try different down payment amounts, interest rates, and loan terms to find the option that fits your budget and goals.