Simple Mortgage Calculator

Use this free, simple mortgage calculator to help you understand the real cost of buying a home before you sign any paperwork

What is a Simple Mortgage Calculator?

A simple mortgage calculator helps you understand the real cost of buying a home before you sign any paperwork. When you’re looking at houses, it’s easy to focus on the listing price and forget about everything else that goes into your actual monthly payment. This tool changes that by showing you the complete financial picture in seconds.

Enter a few key numbers—the home’s price, how much you’re putting down, your interest rate, and how long you’ll be paying—and you’ll instantly see what you’ll owe each month.

But the calculator goes further than that. It includes property taxes and homeowners’ insurance, giving you the true total of what housing will cost you every month. You’ll also see how much interest you’ll pay over the life of the loan, which often surprises people.

Breaking Down What You Need to Enter

Home Price – Start with what the house costs. This is the seller’s asking price before you negotiate or put any money down. Everything else flows from this number.

Down Payment – How much cash you’re bringing to the table right now. More money down means less to borrow, which means smaller monthly payments and less interest piling up over the years. The calculator shows you what percentage of the home price you’re covering, which matters because hitting 20% usually means you won’t have to pay for private mortgage insurance—a nice chunk of savings.

Interest Rate – What the lender charges you annually to borrow their money. Your credit score heavily influences this number, along with market conditions and which lender you choose. This is where shopping around pays off big time.

Loan Term – How many years you’ll spend paying back the loan. Most people pick 30 years for lower monthly payments, or 15 years to pay less interest overall despite higher monthly bills. The choice depends on what your budget can handle now versus what you want to pay in total.

Annual Property Tax – What your local government charges you each year to own the property. This varies wildly depending on where you live. Your lender usually collects this monthly along with your mortgage payment, holds it in escrow, then pays the tax bill when it’s due.

Annual Home Insurance – Your yearly insurance premium protecting the house. Lenders require this, and like property taxes, it typically gets bundled into your monthly payment and held in escrow until the insurance company needs to be paid.

How the Math Works Behind the Scenes

The calculator runs through a specific sequence to figure out your costs:

Finding Your Loan Amount

It starts simple: subtract your down payment from the home price. That’s how much you’re borrowing.

Calculating Your Monthly Principal and Interest

Here’s where the standard mortgage formula comes in:

Monthly Payment = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1]

P is what you’re borrowing. R is your monthly interest rate (yearly rate divided by 12). N is how many monthly payments you’ll make.

This formula makes sure each payment covers that month’s interest plus chips away at what you owe, guaranteeing everything gets paid off on time.

Adding in Taxes and Insurance

Your annual property tax and insurance get split into 12 monthly chunks and added to your payment.

Getting Your True Monthly Total

Add up your principal, interest, property tax, and insurance. That’s your real monthly housing cost—what you absolutely need to budget for.

Calculating Total Interest

Multiply your monthly principal and interest payment by how many months you’ll be paying. Subtract what you originally borrowed. What’s left is pure interest—what borrowing costs you beyond just repaying the loan.

Mapping Your Loan’s Journey

The calculator then tracks your loan year by year, showing how much principal you pay down, how much goes to interest, and what you still owe. Early on, most of your payment is interest. Gradually, that flips until you’re mostly paying down the actual loan in later years.

What Your Results Mean

Monthly Payment – Your principal and interest payment to the lender. With a fixed-rate mortgage, this stays the same every month for the entire loan.

Total Interest – The complete cost of borrowing. On a typical 30-year mortgage, you might pay almost as much in interest as you borrowed originally. This number makes the case for why even small rate differences matter enormously.

Total Paid – Everything you’ll pay the lender from start to finish. Principal plus every interest dollar.

Payment Breakdown – See exactly how your monthly payment splits between the mortgage itself, property taxes, and insurance. The pie chart makes it visual—you can quickly gauge whether your payment is mostly going to the lender or to taxes and insurance.

Amortization Summary – Watch your first five years unfold. Each year shows how much principal you paid down, how much went to interest, and what you still owe. Early years are brutal—you’re paying mostly interest. But it gets better as your balance shrinks.

Why This Matters

Lenders and real estate agents love to focus on one question: “Can you afford this monthly payment?” But that’s incomplete. What about the $150,000 in interest you might pay over 30 years? What about how a bigger down payment now could save you $40,000 long-term? What about whether stretching for a 15-year mortgage would actually work with your income?

This calculator answers those questions. You’ll discover concrete trade-offs. Maybe putting down 20% instead of 10% drops your payment by $180 monthly and eliminates PMI. Maybe a 15-year mortgage costs $650 more monthly but saves you $120,000 in interest. Maybe a rate that’s 0.75% better saves you $80 monthly and $30,000 over the loan’s life.