Mortgage Calculator

About the Mortgage Calculator

Buying a home is the largest financial decision most people will ever make, and understanding your mortgage payment is the critical first step. A mortgage calculator allows you to estimate your monthly principal and interest payment before you even set foot in a bank, giving you the confidence to shop for homes within your true budget.

This calculator uses the standard amortization formula used by banks and lenders worldwide. Enter your home price, down payment, annual interest rate, and loan term to compute your fixed monthly payment, the total interest you will pay over the life of the loan, and a year-by-year breakdown showing how each payment is split between principal and interest.

Understanding these numbers helps you compare offers from multiple lenders, decide between a 15-year and a 30-year term, and see the dramatic impact that even a small rate difference — say 6.0% vs 6.5% — has on your lifetime cost. Most borrowers are surprised to learn that on a 30-year loan, they often pay more in interest than the original amount borrowed.

When This Page Helps

Before you start house-hunting, you need to know what you can actually afford. Pre-qualification letters from lenders tell you the maximum you could borrow, but that ceiling is rarely what you should borrow. This calculator lets you run "what-if" scenarios in seconds: What if I put 20% down instead of 10%? What if I choose a 15-year term? What if I make one extra payment per year?

Real estate agents, loan officers, and financial advisors all recommend running these numbers before making an offer. It protects you from overextending your budget and helps you negotiate from a position of knowledge.

How to Use the Inputs

1. Enter the total home price — the full asking or offer price of the property.
2. Enter your down payment as a percentage. The calculator subtracts this from the home price to get your loan amount.
3. Enter the annual interest rate your lender has quoted (e.g., 6.5%).
4. Select the loan term — 30 years is standard, but 15 and 20 years are common alternatives.
5. Optionally enter an extra monthly payment to see how additional principal payments accelerate your payoff.
6. Review your monthly payment, total interest, total cost, and the year-by-year amortization breakdown.

Example Calculation

Tips & Best Practices

• Put at least 20% down to avoid Private Mortgage Insurance (PMI), which costs 0.5%–1% of the loan amount per year.
• Even 0.25% lower interest saves thousands over 30 years — always shop at least 3 lenders.
• Making one extra payment per year shaves 4–5 years off a 30-year mortgage.
• Your total housing cost includes principal, interest, taxes, insurance, and possibly HOA fees — budget for all of them.
• Consider a 15-year term if you can afford the higher payment — you will pay less than half the total interest.
• Bi-weekly payments (26 half-payments/year) effectively make 13 full payments instead of 12, accelerating payoff.

Understanding Mortgage Amortization

When you make a mortgage payment, it is split between interest and principal. In the early years, most of each payment goes to interest. On a $320,000 loan at 6.5%, your first monthly payment of $2,023.65 includes $1,733 in interest and only $291 toward principal. By year 15 the split is roughly even, and in the final years almost all of each payment reduces principal.

Fixed Rate vs. Adjustable Rate Mortgages

A fixed-rate mortgage locks in your interest rate for the entire term — your payment never changes. An adjustable-rate mortgage (ARM) starts with a lower rate for an introductory period (commonly 5 or 7 years) then adjusts annually. ARMs can save money if you sell or refinance before the adjustment, but carry the risk of rising rates.

The True Cost of a Mortgage

Borrowers often focus on the monthly payment, but total cost matters more. A $320,000 loan at 6.5% for 30 years costs $728,514 total — more than double the loan. A 15-year term at 5.8% brings total cost to $479,760 — saving nearly $249,000.

Frequently Asked Questions

• What is a mortgage?

  A mortgage is a secured loan used to purchase real estate. The property itself serves as collateral — if you stop making payments, the lender can foreclose. Most mortgages are fully amortizing, meaning each payment covers both interest and a portion of the principal until the loan is paid off.

• How does the interest rate affect my monthly payment?

  The interest rate has a huge impact. On a $300,000, 30-year loan, the difference between 6.0% and 7.0% is about $200/month and over $72,000 in total interest. Even a quarter-point difference changes the monthly payment by roughly $50 and total interest by $18,000.

• Should I choose a 15-year or 30-year mortgage?

  A 15-year mortgage has higher monthly payments (roughly 40–50% more) but a lower interest rate and far less total interest — often less than half. Choose 15 years if you can comfortably afford it; choose 30 years for flexibility with the option to pay extra.

• What is included in my actual monthly payment?

  This calculator shows principal and interest (P&I). Your actual payment usually also includes property taxes and homeowners insurance (often escrowed), and possibly PMI — collectively called PITI.

• How much house can I afford?

  The 28/36 rule says spend no more than 28% of gross monthly income on housing costs and no more than 36% on total debt. A household earning $8,000/month should keep total housing under $2,240.

• What is PMI and when can I remove it?

  Private Mortgage Insurance is required when your down payment is less than 20%. It costs 0.5%–1% of the loan per year. Lenders must automatically cancel PMI when your balance hits 78% of the original home value.

• How do extra payments help?

  Extra payments go directly toward reducing principal. Since interest is calculated on the remaining balance, reducing it faster means less interest accrues. Even $100/month extra can save tens of thousands of dollars and years off a 30-year mortgage.

• Is this calculator accurate?

  It uses the exact amortization formula banks use, so P&I is accurate. It does not include property taxes, insurance, PMI, or HOA, which vary by location.