Compute total mortgage interest over the life of the loan.
Please do not make financial decisions based on these results.
What is the Mortgage Interest Calculator?
Compute total mortgage interest over the life of the loan. To use the Mortgage Interest Calculator, enter loan, rate, term; it returns total interest, interest first year, and shows them instantly as you type.
Where the Mortgage Interest Calculator fits
Compute total mortgage interest over the life of the loan. The main figure it returns is the Total interest, worked out from the values you enter.
It belongs with the other loans & debt tools. If you are comparing options or checking a result from another angle, try the Loan Interest Calculator, Credit Card Interest Calculator or the Interest Per Day Calculator.
How to use the Mortgage Interest Calculator
- Fill in the fields. You will need Loan ($), Rate (%), Term (years). Take the rate and term from your loan offer. Fees and the rate type change the result. Fields marked optional can stay at zero.
- Read the result. The highlighted box gives the Total interest, and the cards below show Interest first year. Tables and charts break it down further.
- Test other scenarios. Results update as you type. Change one value at a time to see what drives the answer, and press Reset to go back to the defaults.
Formula and how it works
Example with real numbers
Here is the Mortgage Interest Calculator using the default values shown in the calculator above:
Inputs
| Loan ($) | 350,000 |
|---|---|
| Rate (%) | 6.5 |
| Term (years) | 30 |
Results
| Total interest | $446,405.71 |
|---|---|
| Interest first year | $22,634.82 |
With these inputs the calculator returns Total interest: $446,405.71. Change any value in the calculator to see how the result moves.
What if you change one input?
Sensitivity check: raising Loan ($) from 350,000 to 420,000 (about 20% higher) and leaving everything else as in the example above changes the results like this:
| Result | Example | After the change | Change |
|---|---|---|---|
| Total interest | $446,405.71 | $535,686.85 | +20% |
| Interest first year | $22,634.82 | $27,161.78 | +20% |
The input that moves the result most is the one to check twice. Change it in the calculator above to test your own case.
What the results tell you
The results panel of the Mortgage Interest Calculator reports Total interest and interest first year. Compare these figures while changing one input at a time, and use the related calculators below to look at the same situation from another angle.
Method and limits. This calculator applies the formula in the section above to your inputs, in your browser; nothing you enter is stored on our servers. Your lender’s offer is the final word: fees, rate type and rounding differ between lenders. It is for information, not financial, tax or legal advice.
Frequently asked questions
How much interest will I pay?
On a 30-year loan at 6.5% interest is roughly 128% of the amount borrowed.
How can I pay off a loan faster?
Pay more than the required amount, add extra yearly or one-time payments, or switch to biweekly payments. Make sure extra payments go to principal.
What is APR and why does it matter?
APR is the yearly cost of a loan including fees. Use it, rather than the interest rate alone, to compare offers.
Are the results guaranteed?
No. Results depend entirely on the numbers you enter and the formulas shown on this page. Please do not make financial decisions based on them alone; confirm important figures with a licensed professional.
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