This fixed-rate mortgage calculator estimates the monthly principal-and-interest payment that pays a home loan down to zero over a set term. Enter the amount borrowed, the annual interest rate, and the length of the loan in years. The result assumes every payment is made on time and the rate never changes.
The figure is only the loan payment. Property taxes, homeowners insurance, mortgage insurance, and HOA dues are real parts of a housing bill, but they are not part of the amortization formula, so this page does not guess them. Use the result to compare a rate or a shorter term before you talk with a lender. It is a planning estimate, not a Loan Estimate or an approval.
How to use this calculator
- Enter the amount borrowed in US dollars. The sample value is 300,000.
- Enter the annual interest rate as a percent. For 6.5%, type 6.5, not 0.065.
- Enter the term in years. A 30-year mortgage uses 30, which is 360 monthly payments.
- Press Calculate. The headline is the monthly principal-and-interest payment. Total repayment and total interest appear underneath.
How a fixed-rate mortgage payment is calculated
The calculator converts the annual percentage rate into a monthly rate by dividing by 100 and then by 12. A 6.5% rate becomes 0.065 / 12. It then counts the payments as years times 12. Those two numbers, plus the principal, are the only inputs to the standard fully amortizing loan formula.
Each monthly payment covers that month's interest on the remaining balance and puts the rest toward principal. Early payments are mostly interest. Later payments retire principal faster. The tool does not print a full amortization schedule. It reports the level payment, the sum of every payment, and the interest portion of that sum.
If the rate is exactly zero, there is no interest to compound. The payment is the principal divided by the number of months, and total interest is zero. Negative rates, extra principal payments, interest-only periods, and adjustable rates are outside what this form models.
Formula
Monthly rate r = annual percent / 100 / 12 Payments n = years × 12 If r = 0: payment M = principal / n Otherwise: M = principal × r × (1 + r)^n / ((1 + r)^n − 1) Total repayment = M × n Total interest = total repayment − principal
The payment used in that total is the full-precision result, not the cents-rounded figure in the headline. Because of that, the on-screen monthly payment multiplied by the number of months can differ by a dollar or two from the on-screen total repayment. Both lines are rounded for display on their own.
This is the ordinary US fixed-rate convention: a nominal annual rate divided by 12, with monthly payments in arrears. A lender that uses a different day count, biweekly payments, or a rate that is already a monthly rate will not match.
Worked mortgage examples
$300,000 at 6.5% for 30 years
Principal is 300,000, the annual rate is 6.5, and the term is 30 years, so there are 360 payments. The monthly rate is 6.5 / 100 / 12. The calculator shows a payment of $1,896.20 / month, total repayment of $682,633.47, and total interest of $382,633.47.
Multiplying the rounded payment by 360 gives $682,632.00, which is $1.47 less than the displayed total. That gap is display rounding, not a second fee. Interest here is more than the amount borrowed because the balance is outstanding for three decades.
The same loan on a 15-year term
Keep 300,000 and 6.5%, and change the term to 15 years (180 payments). The calculator shows $2,613.32 / month, total repayment of $470,397.98, and total interest of $170,397.98.
The monthly bill is $717.12 higher than the 30-year payment, and total interest is $212,235.49 lower. A shorter term costs more each month and less over the life of the loan. This comparison still excludes taxes, insurance, and any mortgage insurance a smaller down payment might require.
A lower rate, and a zero-interest check
At 3% for 30 years on $300,000, the calculator shows $1,264.81 / month, total repayment of $455,332.36, and total interest of $155,332.36. Dropping the rate from 6.5% to 3% cuts the payment by $631.39 and cuts interest by $227,301.11 on this particular loan. Rate and term both matter, and they do not trade off in a straight line.
At 0% for 30 years, the payment is 300,000 / 360. The calculator shows $833.33 / month, total repayment of $300,000.00, and total interest of $0.00. That zero-rate case is a useful check that the form is dividing principal by the number of payments when there is nothing to compound.
Payment comparison for fixed monthly loans
| Loan | Rate | Term | Monthly payment | Total repayment | Total interest |
|---|---|---|---|---|---|
| $300,000 | 6.5% | 30 years | $1,896.20 | $682,633.47 | $382,633.47 |
| $300,000 | 6.5% | 15 years | $2,613.32 | $470,397.98 | $170,397.98 |
| $300,000 | 3% | 30 years | $1,264.81 | $455,332.36 | $155,332.36 |
| $400,000 | 7% | 30 years | $2,661.21 | $958,035.59 | $558,035.59 |
| $300,000 | 0% | 30 years | $833.33 | $300,000.00 | $0.00 |
What this mortgage estimate leaves out
A real monthly housing payment often adds one-twelfth of the annual property tax and homeowners insurance, and sometimes mortgage insurance. Those amounts depend on the house, the down payment, and the insurer. Adding a round number yourself is more honest than hiding an assumed tax rate inside the formula.
The form also ignores discount points, origination fees, extra principal payments, biweekly schedules, interest-only periods, balloons, and adjustable rates. Paying extra principal would shorten the loan and reduce interest, but you would need an amortization schedule to see the new payoff date. This page cannot produce that schedule.
Lenders may round the payment to the cent using their own rule, so a quote can differ by a few cents from the figure here even when the rate, amount, and term match. Use a matching quote as a check, not as proof that either number is the contract payment.
A payment in dollars also says nothing about tax taken out of a salary. If the income you would use to cover housing is taxed in England, Wales, or Northern Ireland, estimate that 2026/27 take-home pay separately and keep the currencies apart. This mortgage form does not convert pounds to dollars.
Frequently asked questions
Does this mortgage payment include property tax and insurance?
No. The result is principal and interest only. Taxes, homeowners insurance, mortgage insurance, and HOA dues are not estimated, because they are not determined by the amortization formula.
Why does a 15-year mortgage cost more each month and less overall?
The same balance is spread over 180 payments instead of 360, so each payment is larger. The balance also spends less time accruing interest, so the interest total falls. On the $300,000, 6.5% example, the 15-year payment is $2,613.32 and total interest is $170,397.98, against $1,896.20 and $382,633.47 over 30 years.
Should I type 6.5 or 0.065 for a 6.5% mortgage rate?
Type 6.5. The calculator divides the rate by 100 and then by 12. Entering 0.065 would be treated as a 0.065% annual rate, which is not a 6.5% mortgage.
Why does the monthly payment times the number of months miss the total?
Each displayed amount is rounded to the cent from the full-precision result. For the 30-year, 6.5%, $300,000 example, $1,896.20 times 360 is $682,632.00, while the displayed total repayment is $682,633.47. The $1.47 gap is rounding, not an extra charge.
Will this match a lender Loan Estimate?
Only the principal-and-interest line can be close, and only when the amount, note rate, and term match and the loan is a standard fixed monthly payment. A Loan Estimate also includes fees, escrow, and prepaid items that this calculator never sees.
Related ClearCalc pages
- 2026/27 take-home pay calculator for England, Wales and Northern Ireland Use it for the income side when the salary is taxed there. Do not subtract a sterling result from this dollar payment.
- Personal and auto loan calculator The same amortization formula, aimed at shorter installment loans.
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- England stamp duty calculator Residential SDLT in pounds for a purchase in England or Northern Ireland. It is not added to this dollar loan payment.
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