Mortgage Calculator
Find out your monthly mortgage payment, total interest cost, and overall price of your home loan. Compare 15-year vs 30-year terms and see how extra payments save you money.
Background
A mortgage calculator estimates your monthly home loan payment based on the purchase price, down payment, interest rate, and loan term. It shows how much of each payment goes to interest vs. principal and the total cost over the life of the loan.
This free mortgage calculator gives instant results as you adjust any input. Compare different loan terms, see the impact of a larger down payment, or test what happens when rates change by half a percent.
Enter your home price
Type the full purchase price of the home. Then enter your down payment — the amount you'll pay upfront. The calculator computes the loan amount (home price minus down payment) and uses your interest rate and term to find the monthly payment.
How to use this mortgage calculator
Four inputs, instant answer:
Enter the home price
Type the full purchase price. You can also enter just the loan amount and set the down payment to $0.
Set the interest rate
Type your rate or drag the slider. Even small changes — like 6.5% vs 7.0% — make a big difference over 30 years.
Read the results
Your monthly payment, total interest, and total cost appear instantly. Compare terms by tapping 15yr vs 30yr.
How this mortgage calculator works
It uses the standard amortization formula that banks use. Each monthly payment covers part interest and part principal. Early payments are mostly interest; later payments are mostly principal.
Formula & Equation Used
The standard fixed-rate mortgage payment formula:
Where: M = monthly payment, P = loan principal, r = monthly interest rate (annual ÷ 12), n = total number of payments (years × 12).
Try it yourself
Example Problem & Step-by-Step Solution
You want to buy a $400,000 home with 20% down ($80,000) at 6.75% interest on a 30-year fixed mortgage. What's the monthly payment and total interest?
That $320,000 loan costs you $747,065 in total ($320K principal + $427K interest). A 15-year term at the same rate would cost $2,830/mo but only $189,427 in total interest — saving you $237,638.
Frequently Asked Questions
How much house can I afford?
A common guideline: your monthly mortgage payment should be no more than 28% of your gross monthly income. If you earn $6,000/month, aim for a payment under $1,680. But also factor in property taxes, insurance, and maintenance.
What's the difference between fixed and adjustable rates?
A fixed-rate mortgage locks in the same interest rate for the full loan term. An adjustable-rate mortgage (ARM) starts with a lower rate that can change periodically after an initial fixed period (like 5 years). ARMs can go up or down based on market rates.
Should I get a 15-year or 30-year mortgage?
A 15-year mortgage has higher monthly payments but saves you a massive amount in interest. A 30-year gives you lower monthly payments and more flexibility. Use this calculator to compare both — the interest savings are often hundreds of thousands of dollars.
Does this include property tax and insurance?
This calculator shows principal and interest only. Your actual monthly payment will also include property taxes (~1-2% of home value per year) and homeowner's insurance (~$100-300/month). Some lenders bundle these into an escrow payment.
What is a mortgage?
A mortgage is a loan used to buy real estate. The property itself serves as collateral — if you stop making payments, the lender can take the property through foreclosure. Most home buyers can't pay cash, so mortgages make homeownership possible by spreading the cost over 15-30 years.
The word "mortgage" comes from Old French, meaning "death pledge." Not because it's dangerous — but because the pledge "dies" when the debt is paid off or the property is sold.
Key mortgage milestones in the US
How interest rates affect your payment
Small rate changes have an outsized impact on a 30-year loan. Here's what a $300,000 loan costs at different rates:
From 5% to 8%, your monthly payment increases by $591 — and total interest nearly doubles. That 3-point rate difference costs $212,760 over 30 years.
Mortgage numbers
Types of mortgages
Fixed-rate mortgage
Adjustable-rate (ARM)
FHA loan
Calculator features explained
Home price & down payment
Enter the purchase price and how much you'll put down. The loan amount is calculated automatically.
Interest rate
Type your quoted rate or use the slider. Even 0.25% makes a noticeable difference on a large loan.
Loan term
Pick 10, 15, 20, or 30 years. Shorter terms have higher payments but dramatically lower total interest costs.
Copy results
Hit Copy to send your payment breakdown to the clipboard. Share with your partner or mortgage broker.
FAQ
What is PMI and when do I need it?
Private Mortgage Insurance (PMI) is required when your down payment is less than 20% of the home price. It protects the lender, not you. PMI typically costs 0.5-1% of the loan annually. It's removed once you reach 20% equity.
Can I pay off my mortgage early?
Yes. Most mortgages have no prepayment penalty. Adding even $100/month extra to your payment can shave years off the loan and save tens of thousands in interest. Direct extra payments toward the principal.
What credit score do I need for a mortgage?
Conventional loans typically need 620+. FHA loans accept 580+ (with 3.5% down) or even 500-579 (with 10% down). Higher scores get better rates — a 760+ score might save you 0.5-1% on your rate compared to a 620 score.