Mortgage Calculator
Estimate your monthly mortgage payment including principal, interest, taxes, and insurance.
Cómo funciona
This calculator estimates your full monthly mortgage payment — often called PITI, short for Principal, Interest, Taxes, and Insurance — rather than just the loan portion.
It starts by subtracting your down payment from the home price to get the loan amount, then applies the standard amortization formula (the same one lenders use) to spread principal and interest evenly across the loan term. It then adds your annual property tax and homeowners insurance, divided by 12, to get the full monthly payment.
For example, on a $350,000 home with a $70,000 down payment (20%), a $280,000 loan at 6.5% over 30 years amortizes to about $1,770/month in principal and interest. Add $3,600/year in property tax ($300/mo) and $1,200/year in insurance ($100/mo), and the full monthly payment comes to roughly $2,170.
Down payment size matters beyond just lowering the loan amount: putting down less than 20% typically triggers Private Mortgage Insurance (PMI) on conventional loans, an extra monthly cost this calculator doesn't add automatically — fold it into the annual insurance field if it applies to you.
Loan term is a real tradeoff, not just a preference: a 15-year mortgage carries a noticeably higher monthly payment than a 30-year mortgage on the same loan amount, but pays off far less total interest over the life of the loan since the balance is repaid twice as fast.
A common rule of thumb lenders use for affordability is the 28/36 rule: your total housing payment (PITI) should generally stay under 28% of your gross monthly income, and all debt payments combined (housing plus car loans, student loans, credit cards) under 36%. These aren't hard limits — actual approval depends on the specific lender, your credit, and other factors — but they're a reasonable sanity check when using this calculator to explore what home price fits your budget.
If rates drop significantly after you've taken out a mortgage, refinancing — replacing your existing mortgage with a new one, ideally at a lower rate or better terms — can meaningfully lower your monthly payment or reduce total interest. This calculator can model a potential refinance the same way as a new mortgage: enter the remaining loan balance as the "home price" with $0 down payment, plus the new rate and term, to estimate the new payment.
Is PMI included?
Not automatically — add it to the annual insurance field if it applies to your loan.
How much should my down payment be?
20% avoids PMI on most conventional loans, but many buyers put down less. A smaller down payment means a larger loan, a higher monthly payment, and likely PMI until you reach 20% equity.
15-year vs 30-year mortgage — which is better?
A 15-year loan has a higher monthly payment but far less total interest paid over the loan's life. A 30-year loan is more affordable month-to-month but costs more in total interest. The right choice depends on your monthly budget versus your long-term cost priorities.
What is escrow, and how does it relate to this calculator?
Escrow is an account many lenders use to collect your property tax and insurance monthly (as part of your mortgage payment) and pay them on your behalf when due — which is exactly what the tax and insurance fields in this calculator estimate.
How does the interest rate affect my monthly payment?
Even a small rate change has a big effect over a 30-year term — for example, moving from 6% to 7% on a $280,000 loan increases the monthly principal and interest payment by roughly $160.
What other homeownership costs aren't included here?
HOA fees, routine maintenance, utilities, and PMI (unless you add it to the insurance field) aren't included — budget for these separately when deciding what you can afford.
How is the loan amount calculated from home price and down payment?
Loan amount = home price − down payment. That figure is what actually gets amortized over your chosen loan term.
What's the 28/36 rule lenders use for affordability?
A guideline where your total housing payment stays under about 28% of gross monthly income, and all debts combined stay under about 36% — a useful sanity check, though actual lending decisions depend on many other factors too.
How can I use this calculator to estimate a refinance?
Enter your remaining mortgage balance as the home price, $0 as the down payment, and the new interest rate and term you're considering — the result approximates what your new monthly payment would be.