Extra Payment Savings Calculator
Simulate a loan with and without a recurring extra monthly payment to see how much time and interest a consistent extra payment saves.
$
%
months
$
Interest Saved
$754.98
Time Saved
13 months
Baseline Payoff
60 months
New Payoff With Extra
47 months
How to Use the Extra Payment Savings Calculator
Enter your loan principal, annual interest rate, and term, plus an extra amount you plan to add to every monthly payment. The calculator simulates the loan month by month twice: once with only the standard payment, and once adding your extra amount to principal every single month. Because the extra amount reduces the balance faster, less interest accrues each month, which shortens the payoff time and reduces total interest paid.
Each month: Interest = Balance × r; Principal Paid = Payment (+ Extra) − Interest
Example
A $20,000 loan at 6% over 60 months has a standard payment of about $386.66/month, paying off in 60 months with about $3,199.36 in total interest. Adding $100 extra every month instead pays it off in 47 months, saving roughly $754.98 in interest.
Common Use Cases
- Deciding whether to commit to a recurring extra monthly payment on a car, personal, or student loan.
- Seeing exactly how many months sooner a loan is paid off with a modest recurring extra amount.
- Comparing different extra-payment amounts to find one that fits your budget while still meaningfully cutting interest.
FAQs
- How is this different from the Mortgage Recast Calculator? Mortgage recasting is a ONE-TIME lump-sum payment that lowers your monthly PAYMENT while keeping the original term the same. This tool instead models a RECURRING extra amount added every month on top of your existing payment — the payment stays higher than the minimum, but the loan pays off FASTER and saves interest, rather than lowering the payment.
- How is this different from the Debt Payoff Calculator? The Debt Payoff Calculator handles MULTIPLE debts at once using Snowball or Avalanche strategies to decide which debt gets extra payments first. This tool is for a SINGLE loan only, showing the direct effect of adding one extra amount to that one loan's payment every month.
- Does the extra payment need to stay the same every month? This calculator assumes a fixed extra amount every month for simplicity. In reality, even irregular extra payments will still shorten your payoff time and save interest — just re-run the calculator with an average extra amount for a rough estimate.