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Mortgage Calculator
Before you commit, you want the real monthly number — taxes, insurance, PMI and HOA on top of principal & interest. This mortgage calculator adds it up, with your payoff date and what extra payments save.
See how this works on a $450,000 house — 3 real examples
Total monthly payment (month 1)
$0
Loan amount
$0
Total interest
$0
Payoff date
—
Your principal & interest, month by month
- Interest—
- Principal—
This is the principal & interest slice only — escrow (property tax, insurance, PMI and HOA) is a separate, constant amount on top of the figures above.
Loan balance over time
Amortization scheduleMonth-by-month breakdown
How your monthly mortgage payment is calculated
The principal-and-interest payment comes from the standard fixed-rate amortization formula:
M = P · r(1 + r)n / ((1 + r)n − 1)
r = annual rate / 12 n = years × 12
PITI = M + tax/12 + insurance/12 + PMI + HOA
where P is the loan amount (home price minus down payment). Property tax entered as a percent is that percent of the home price per year, so the dollar bill moves when the price does; entered in dollars it is used as-is. Monthly PMI is the annual PMI rate times the original loan amount, divided by 12 — or, in dollar mode, the monthly premium you typed, used directly. Either way it is charged only while the beginning-of-month balance exceeds 80% of the home price — the drop-off month comes from the real amortization schedule, not an approximation.
Extra payments are added to M each month and applied entirely to principal, with the final payment clamped so the balance lands exactly on zero; interest saved is the difference in total interest between the baseline and accelerated schedules.
Assumptions: the rate is fixed for the whole term, the first payment lands one month from today (payoff and schedule dates follow from that), taxes and insurance are held constant, and the PMI drop-off month is computed on the standard schedule without extra payments.
One house, three ways to pay for it
Three ways to carry the same $450,000 house at 6.5%. The down payment changes one thing; the clock changes something much bigger.
The easier start: 10% down, 30 years
per month$3,341.13
- The cheapest way in: $45,000 opens the door where the other two ask for twice that.
- Mortgage insurance tags along at $168.75 a month for almost eight years, collecting $16,031 before it quits.
- Across 30 years, interest alone comes to $516,555, more than the price of the house.
You keep $45,000 in your pocket today and pay for it every month for thirty years.
Load this example (opens in a new tab)The classic: 20% down, 30 years
per month$2,887.94
- Doubling the down payment to $90,000 makes the mortgage insurance line disappear.
- Each month runs $453.18 lighter than the 10% version.
- Even so, thirty years of interest adds up to $459,160.
Twice the cash to start, the smallest bill each month, and no insurance for the loan.
Load this example (opens in a new tab)The sprint: 20% down, 15 years
per month$3,748.49
- Fifteen years instead of thirty, and the bill climbs by $860.54 a month over scenario B.
- In return, $254,683 of interest never gets charged at all.
- Total interest stops at $204,478, less than half of what either thirty-year plan pays.
The steepest monthly bill of the three, and the meter stops running fifteen years sooner.
Load this example (opens in a new tab)Illustrations only, not financial advice. Your own rate, taxes and insurance will differ — check with a qualified financial advisor before acting on any of this.
Home mortgage basics, in plain English
- PITI is the real payment. Lenders advertise principal & interest, but they qualify you on the full total — plus escrowed tax and insurance, and PMI or HOA if they apply.
- PMI comes off automatically. It’s charged only below 20% down and drops at 80% LTV — this calculator marks the exact month on the chart.
- Amortization front-loads interest. On a 30-year loan at 6.5%, principal doesn’t overtake interest until about year 19, so early equity builds slowly.
- Extra payments punch above their weight. $100/mo on the default loan saves roughly $61,700 and pays off nearly four years early — and early extra dollars do the most work.
- Garbage in, garbage out. Property tax averages ~1.1% of value but ranges from <0.3% to >2% by county; get rate quotes from at least three lenders.
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Frequently asked questions
How is my monthly mortgage payment calculated?
This mortgage calculator uses the standard amortization formula lenders rely on: M = P × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), where P is the loan amount, r the monthly interest rate and n the number of payments. On a $320,000 loan at 6.5% for 30 years that works out to $2,022.62 for principal and interest. Property taxes, homeowners insurance, PMI and HOA dues are then added on top to get your true monthly cost.
What is included in a monthly mortgage payment (PITI)?
PITI stands for principal, interest, taxes and insurance — the four core pieces of a mortgage payment. Principal pays down the loan, interest is the lender’s charge, and most borrowers also escrow one-twelfth of their annual property tax and homeowners insurance each month. If you put less than 20% down you’ll usually pay PMI as well, and condos or planned communities add HOA dues.
What is PMI and when does it go away?
Private mortgage insurance protects the lender when your down payment is below 20%, and typically costs 0.3%–1.5% of the loan amount per year. With 10% down on a $400,000 home at 6.5%, a 0.5% PMI rate adds $150 a month until the balance reaches 80% of the home’s value around payment 96 — about $14,250 of total PMI. By federal law PMI must terminate automatically at 78% LTV, and you can request cancellation at 80%.
How does the loan term affect my mortgage payment?
Shorter terms trade a higher payment for dramatically less interest. Borrowing $320,000 at 6.5% costs $2,022.62 a month over 30 years but $2,787.53 over 15 years — about $765 more per month, yet total interest falls from roughly $408,000 to $182,000. 15-year loans also usually carry lower rates than 30-year loans, which widens the gap even further.
Why does the interest rate have such a big impact on my payment?
Because interest is charged on the balance every month across hundreds of payments. On a $320,000 30-year loan, moving from 6.5% to 7.5% raises the payment about $215 a month and adds roughly $77,000 of lifetime interest. That is why shopping several lenders and comparing APRs — even for a 0.25% difference — is worth the effort, whether you’re buying or refinancing.
How much can I save with an extra $100 a month?
More than most people expect. Adding $100 a month to a $320,000 loan at 6.5% over 30 years pays it off 46 months — nearly four years — early and saves about $61,700 in interest. Enter any amount in the extra-payment field above and the payoff date, chart and schedule update instantly.
How much house can I afford?
A common starting point is the 28/36 rule: keep housing costs under 28% of gross monthly income and all debt payments under 36%. On a $96,000 salary that is a housing budget of about $2,240 per month including taxes and insurance. You can work backwards in this calculator by adjusting the home price until the total monthly payment fits your budget.
Disclaimer: these calculators are educational tools, not financial advice. They model your inputs with published formulas, but they cannot know your full situation — for decisions with real stakes, talk to a qualified professional. Formulas and defaults last reviewed .