Mortgage Calculator
Estimate your monthly principal & interest payment, see the total interest a home loan really costs, and explore the full amortization schedule.
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Monthly payment (principal & interest)
$0.00
- Principal $0
- Interest $0
Excludes taxes, insurance, PMI, and HOA dues.
Balance and interest over time
How your remaining balance shrinks while cumulative interest grows.
- Remaining balance
- Cumulative interest
Year-by-year amortization schedule
| Year | Interest | Principal | Ending balance |
|---|
Compare two scenarios
Same loan amount as above, two rate/term combos side by side. Classic matchup: 30-year vs 15-year.
Scenario A
Scenario B
| Scenario A | Scenario B | B − A | |
|---|---|---|---|
| Monthly payment | — | — | — |
| Total interest | — | — | — |
| Total of payments | — | — | — |
| Payoff date | — | — | — |
How it works
A fixed-rate mortgage is an amortizing loan: you pay the same amount every month, and each payment is split between interest and principal. The monthly payment formula is:
Where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of monthly payments. If the rate is 0%, the payment is simply the loan amount divided by the number of months.
What your payment is really made of
Lenders advertise P&I — principal and interest. But the amount that actually leaves your bank account is usually PITI: principal, interest, property tax, and homeowners insurance, often bundled through an escrow account. Put less than 20% down and you'll typically add PMI (private mortgage insurance); condos and many neighborhoods add HOA dues. Together these can add several hundred dollars a month on top of P&I. This calculator isolates P&I so you can see the loan itself clearly — add your local tax and insurance figures for the full monthly picture.
Why early payments are almost all interest
Each month, interest equals the remaining balance times the monthly rate. In year one the balance is at its peak, so interest eats most of the payment. Every dollar of principal you repay shrinks the balance that next month's interest is charged on — which is why the interest/principal split flips over time even though your payment never changes. Open the schedule above to watch the crossover happen year by year.
15-year vs 30-year, and the power of extra payments
A 15-year term typically carries a lower rate and dramatically less total interest — but the monthly payment runs roughly 50% higher than a 30-year loan on the same amount. The 30-year costs more overall yet keeps payments flexible, leaving room to invest the difference. A middle path many borrowers take: choose the 30-year for flexibility, then make extra principal payments when cash allows. Because extra payments attack principal directly, even one additional payment per year can shave years off the loan and save tens of thousands in interest.
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Frequently asked questions
Does this include property taxes and insurance?
No. This calculator shows principal and interest (P&I) only. Most homeowners also pay property taxes, homeowners insurance, and possibly PMI or HOA dues, which can add several hundred dollars per month on top of the P&I payment.
Why is most of my early payment going to interest?
With a fixed monthly payment, interest is charged on the remaining balance each month. Early on the balance is large, so interest takes the biggest share. As the balance shrinks, more of each payment goes toward principal. This pattern is called amortization — see the year-by-year schedule above to watch it happen.
Is a 15-year or 30-year mortgage better?
A 15-year loan usually has a lower rate and far less total interest, but the monthly payment is much higher. A 30-year loan costs more overall but keeps payments lower and more flexible. The right choice depends on your budget and how long you plan to stay.
Do extra payments really save that much interest?
Yes. Extra payments go directly toward principal, which shrinks the balance that future interest is charged on. Even one extra payment per year can cut years off a 30-year loan and save a large amount of interest.
What is PMI and when does it go away?
PMI (private mortgage insurance) protects the lender, not you. It is usually required when your down payment is under 20%, costs roughly 0.3% to 1.9% of the loan amount per year, and can be dropped once your balance falls to 80% of the home's original value — it ends automatically at 78%.
How much house can I afford?
A common guideline is the 28/36 rule: keep housing costs under 28% of gross monthly income and total debts under 36%. Our home affordability calculator applies both rules to estimate your price range from your income, debts, and down payment.