Quick answer: A mortgage payment is computed like any amortizing loan: monthly payment equals principal times monthly rate times the compounding factor over 15 to 30 years. The full housing cost, PITI, adds property taxes and insurance to principal and interest. A bigger down payment lowers the payment and can avoid private mortgage insurance.
Last reviewed: September 2026
Mortgage Payment Calculator
Key facts
- Monthly payment = P × r(1+r)n ÷ [(1+r)n − 1] — r is the monthly rate, n the number of payments.
- A 30-year fixed at 6.5% costs about $1,896/month per $300,000 borrowed — and $382,633 in total interest.
- A 15-year loan of the same size pays roughly $253,000 less in interest, but the monthly bill is higher.
- A single extra $100/month on a 30-year loan can shave years off the schedule.
A mortgage payment is the fixed monthly amount that pays off your home loan — part interest, part principal. This free mortgage calculator computes your monthly payment, total interest, and total cost instantly from the loan amount, rate, and term.
Enter the home price, down payment, interest rate, and loan term. The result appears at once, with a full breakdown of what the loan really costs.
How to use
- Enter the home price and your down payment.
- Enter the annual interest rate and the loan term in years.
- Your monthly payment appears instantly.
- Check the total interest to see the true cost of the loan.
Mortgage payment formula
| Term | Meaning |
|---|---|
| M | Monthly payment (principal + interest only). |
| P | Principal — the amount borrowed after the down payment. |
| r | Monthly interest rate (annual rate ÷ 12). |
| n | Total number of monthly payments (years × 12). |
Example: $300,000 at 6.5% for 30 years → r = 0.0054167, n = 360, so M = $1,896.20/month.
Worked examples
30-year fixed at 6.5%
$300,000, 6.5%, 30 years: monthly payment = $1,896.20. Total paid = $682,633.47, of which $382,633.47 is interest — more than the loan itself.
15-year fixed at 6%
$250,000, 6%, 15 years: monthly payment = $2,109.64. Total interest = $129,735.57 — the shorter term saves a fortune in interest despite the higher monthly bill.
30-year monthly payment per $100,000 borrowed
| Interest rate | Monthly payment | Total interest |
|---|---|---|
| 5.5% | $567.79 | $104,404 |
| 6.0% | $599.55 | $115,838 |
| 6.5% | $632.07 | $127,545 |
| 7.0% | $665.30 | $139,508 |
| 7.5% | $699.21 | $151,716 |
Multiply by your loan size in hundreds of thousands: a $300,000 loan at 6.5% costs 3 × $632.07 = $1,896.20/month.
Frequently asked questions
Does the payment include taxes and insurance?
No. This calculator shows principal + interest only. Your lender’s full PITI payment adds property tax, homeowner’s insurance, and possibly PMI.
Is a 15-year or 30-year mortgage better?
A 15-year loan charges far less total interest, but the monthly payment is much higher. A 30-year loan keeps payments affordable; you can still overpay to mimic a 15-year schedule.
What is PMI?
Private mortgage insurance, usually required when your down payment is under 20%. It protects the lender, not you, and is added to the monthly bill until you reach 20% equity.
How much does 1% of rate change my payment?
On a $300,000 30-year loan, each 1% of rate is roughly $190–$200/month — about $70,000 over the life of the loan.
Do extra payments really help?
Yes. An extra $100/month on a $300,000 6.5% 30-year loan pays it off about 6 years early and saves roughly $75,000 in interest.
Fixed or adjustable rate?
Fixed rates never change — safe and predictable. Adjustable (ARM) rates start lower but can rise later; they suit buyers who plan to sell or refinance within a few years.
Sources
- Bankrate — Mortgage payment calculations
- Federal Reserve — Mortgage and housing finance resources
Key takeaways
- Monthly payment = P × r(1+r)n ÷ [(1+r)n − 1]; longer terms mean lower payments but far more interest.
- On 30-year loans, total interest often exceeds the amount borrowed.
- Small extra payments attack the principal directly and save years of interest.
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