Formula
Interest is every payment minus the amount borrowed:
Total interest = all payments − principal
The payment page leads with the monthly amount. This page leads with the lifetime interest.
Assumptions
- The rate and payment stay fixed.
- No extra principal is paid.
Worked example
A $300,000 mortgage at 6% for 30 years charges $347,515.44 of interest.
Input definitions
- Loan amount
- The principal the interest is calculated on.
Limitations
This is an estimate, not a loan offer, tax filing, or investment advice. The currency control changes the symbol only.
Questions
Does this include property tax?
No. Tax is not interest. Use the property-tax page for an assessed-value tax.
Why is the total so much larger than the loan?
A long term at a typical mortgage rate can charge interest close to the principal itself.