Mortgage Calculator

How to calculate your monthly mortgage payment

Your monthly mortgage payment for principal and interest depends on three numbers: the loan amount (the home price minus your down payment), the interest rate, and the length of the loan. A mortgage calculator combines them with the standard amortization formula to return a single fixed payment that pays the loan off exactly at the end of the term.

To figure out mortgage payment amounts by hand you would convert the annual interest rate to a monthly rate, count the total number of monthly payments, and apply the formula in the next section. The mortgage payment calculator above does all of that instantly — enter the four core fields and it returns your monthly mortgage payment right away. It works as a plain home loan calculator for the base case, and as an online mortgage calculator you can reuse for any scenario you want to compare.

Some people search for a mortgage price calculator when they really mean the payment on a given price; whatever you call it, the goal is the same — to determine mortgage payment size before you commit to a loan.

Mortgage formula

The fixed monthly payment is given by the standard amortization formula:

M = P × r(1 + r)ⁿ / ((1 + r)ⁿ − 1)

where M is the monthly P&I payment (principal + interest), P is the loan amount (home price minus down payment), r is the monthly interest rate (the annual rate divided by 12), and n is the total number of monthly payments (years × 12).

The same equation underlies any monthly mortgage payment, whether the term is 15 years or 30. Because the payment is fixed, the split between interest and principal shifts over time — a topic covered in the amortization section below.

What is P&I (principal and interest)

P&I stands for principal and interest — the two parts of every mortgage payment that go toward the loan itself. The interest portion is the lender's charge for that month, calculated on the outstanding balance. The principal portion is what actually reduces the amount you owe.

Early in a loan the balance is large, so most of each P&I payment is interest and only a little chips away at principal. As the balance falls, the interest share shrinks and the principal share grows, which is why your equity builds slowly at first and then accelerates. The P&I figure is the number this tool reports as your base monthly payment; taxes, insurance, PMI, and HOA dues are added separately when you fill them in.

Mortgage amortization schedule

Mortgage amortization is the process of paying off a loan with equal payments over time, where each payment covers the current month's interest first and applies the rest to principal. The amortization schedule below lists every payment from month one to the final one, showing how much goes to interest, how much to principal, and the balance that remains.

Used this way the tool is an amortization calculator and an amortization table calculator in one: the full amortization schedule is generated for the entire term, and you can expand it from the first year to all payments with a single click. Watching the rows tells the story of the loan — the early months are interest-heavy, the later months principal-heavy, and the balance curves down toward zero.

Mortgage payment with taxes and insurance

The principal and interest figure is only part of what lands in your monthly housing bill. Open the optional section to turn this into a mortgage calculator with taxes, home insurance, PMI, and HOA dues, and the tool will show a full monthly payment alongside the base P&I.

Property taxes can be entered as a dollar amount per year or as a percentage of the home price, so the same mortgage calculator with property taxes adapts to however your local rate is quoted. Add an annual insurance premium and the result becomes a mortgage payment calculator with taxes and insurance combined — together these four parts make up what lenders call PITI (principal, interest, taxes, and insurance). If your down payment is under 20%, enter a PMI rate and the built-in pmi calculator includes private mortgage insurance until you reach 20% equity, after which it normally drops off.

Whether you came here to estimate mortgage payment with taxes folded in, or you simply wanted a house payment calculator with taxes and fees on top of principal and interest, the optional fields cover the complete picture. One thing this tool does not do is adjust for inflation — mortgage payments are fixed in nominal dollars, so a payment that feels heavy today gradually shrinks in real terms; to explore that effect, see our inflation calculator.