Financial Planning
Mortgage Interest Calculator
See how much interest you'll pay — and how extra payments cut it down.
Loan Amount
$
The principal amount you're borrowing
Loan Term
Length of the mortgage repayment period
Interest Rate
6.5%
Annual interest rate on the mortgage
Extra Monthly Payment
$
Optional additional principal paid every month
Is Interest
0%
Monthly Payment
$0
principal & interest, base payment
Total Interest (Standard)
$0
Total Interest (With Extra)
$0
Interest Saved
$0
New Payoff Time
0 yrs
📊 Interest Breakdown
| Item | Amount | % of Loan |
|---|
How the formula works
Monthly Payment = Loan × r ÷ [1 − (1 + r)⁻ⁿ], where r = monthly rate, n = number of payments
- Total Interest (Standard) = (Monthly Payment × n) − Loan Amount
- Extra payments reduce the outstanding balance faster, cutting both total interest and loan term
- Interest Saved = Total Interest (Standard) − Total Interest (With Extra)
- Even small extra payments can meaningfully shorten a 30-year loan