🏠 Mortgage Calculator
See the real monthly cost of a home loan — principal, interest, tax and insurance in one number.
How it works
The heart of it is the standard amortization formula: M = P × r(1+r)n ÷ ((1+r)n − 1), where P is the loan amount, r is the monthly rate (the yearly rate divided by 12) and n is the number of monthly payments. That gives the principal-and-interest part. This calculator then adds your property tax and insurance, spread across the year, plus any HOA dues — because that combined figure is what actually leaves your bank account each month.
An example
On a $300,000 home with $60,000 down, you borrow $240,000. At 7% over 30 years the principal and interest come to $1,596.73 a month. Add $300 a month for tax and $150 for insurance and the real monthly bill is $2,046.73. Over the full term you pay $334,821.36 in interest — more than the loan itself — which is why the rate matters so much on a long loan. In year one, $16,722.77 of your payments is interest and only $2,437.94 comes off the balance.
Common questions
Why is my total payment higher than the loan payment I was quoted?
Quotes usually show only principal and interest. Your lender also collects property tax and home insurance from you each month (escrow) and passes them on, so the amount you actually pay is higher.
How much difference does the rate really make?
A lot, over 30 years. On a $240,000 loan, dropping from 7% to 6% takes roughly $158 off the monthly payment and saves tens of thousands of dollars in interest.
Does a bigger down payment always win?
It cuts the loan, the monthly payment and the total interest, and at 20% down you usually avoid private mortgage insurance (PMI). But it also ties up cash you may need for moving costs, repairs or an emergency fund.
Related calculators
This calculator gives estimates for learning. Rates, taxes and rules change, and your lender or the IRS has the final numbers — check big decisions against the real documents.