Home Loan Calculator

A mortgage is the largest loan people take on. Therefore, small differences in rate, term, and extra payments compound into tens of thousands of dollars. The principal-and-interest payment is fixed for the life of a fixed-rate loan, but the way each payment splits between interest and principal shifts dramatically over 15 or 30 years.

Not sure what you can afford yet? Start with our Home Affordability Calculator.

Before you commit, check how this payment affects your debt-to-income ratio.

This calculator computes your monthly payment and total interest, builds the full amortization schedule, and charts your home's appreciating value against your falling loan balance so you can watch equity build from both directions at once.

How does this calculator work?

Enter your home's purchase price and the amount you're financing. The calculator computes your monthly payment, total interest, and a full amortization schedule.

It's a solve-for-any-field tool: enter a monthly payment instead of a loan amount (or term, or rate) and it back-solves the missing value.

Add an optional extra monthly payment to pay the mortgage off sooner, and set an annual appreciation rate to track your home's value and your growing equity against the loan balance.

Worked example

Take a $400,000 home with 20% down ($80,000), financing $320,000 at 6.5% over 30 years.

Home price

$400,000

Down payment (20%)

$80,000

Loan amount

$320,000

Term / rate

30 yrs / 6.5%

Monthly P&I

$2,023

Total interest (30 yr)

$408,196

How the numbers work

The $2,023 payment is the amortization result for a $320,000 loan at 6.5%, or roughly 0.542% per month over 360 months.

Month one's interest is $320,000 × 0.542% = $1,733, so only about $290 of that first payment actually reduces the loan. That lopsided split is why home equity builds so slowly in the early years. As the balance falls, the interest portion shrinks and the principal portion grows, accelerating equity later in the loan.

Across all 360 payments you repay about $728,000, which is the $320,000 borrowed plus roughly $408,000 in interest, more than the loan itself.

Over 30 years the interest exceeds the amount borrowed. You'd repay more than $728,000 on a $320,000 loan. A 15-year term at the same rate raises the payment to about $2,787 but cuts total interest to roughly $181,500, saving over $226,000.

You don't have to commit to the higher payment to capture much of that benefit: adding $200/month to the 30-year loan retires it about 6 years early and saves more than $90,000 in interest.

15-year vs. 30-year: the real trade-off

A 30-year mortgage minimizes the monthly payment, which maximizes the home you can qualify for and preserves cash flow for other goals. A 15-year mortgage costs far less in total interest and builds equity much faster, but the higher required payment leaves less flexibility if your income dips.

A middle path is to take the 30-year loan for its lower required payment, then voluntarily pay extra toward principal. You can capture most of the interest savings of a shorter term while keeping the lower payment as a safety net for lean months. This is the best of both worlds for many borrowers.

How mortgage equity actually builds

Home equity grows from two independent forces. The first is amortization: each payment retires a little principal, and that share grows every month as the interest portion shrinks. The second is appreciation: if the home's market value rises, your equity climbs even without paying down the loan. The Home Value chart plots both so you can see how quickly your stake in the property grows.

Note this calculator models principal and interest, not the full financing cost you can compare using our mortgage APR calculator. A full housing payment usually also includes property taxes, homeowners insurance, and, if you put less than 20% down, private mortgage insurance (PMI), which typically drops off once you reach 20% equity.