Extra Payment Calculator
Small extras add up fast, because every extra dollar goes straight to principal. Enter your balance, APR, and current payment, then see what an extra $50 or $100 a month does to your payoff date and total interest.
What the extra buys you
How it works
Extra payments are the most powerful lever you have, because they skip the interest line entirely. Your regular payment covers that month's interest first; the extra goes 100% to principal. A smaller balance next month means less interest next month, which means even more of your regular payment reaches principal — the effect compounds.
The numbers are bigger than most people expect. On a $5,000 balance at 24.99% with a $200 payment, adding $100 a month cuts the payoff from 3 years to 21 months and saves roughly $900 in interest. The $100 never feels large month to month; the 15 months it saves feel very large.
Where does the extra come from? It does not need to be a raise. A subscription you don't use, one takeout meal a week replaced by cooking, or the minimum payment from a card you just paid off — rolled forward — all work. The trick is making it automatic: set the extra as part of the payment, not as a decision you remake every month.
Frequently asked questions
Does the extra payment really go to principal?
Yes — as long as your regular payment already covers that month's interest. Card issuers apply payments to interest first, then principal. Any amount above the interest goes straight to the balance.
Is $25 extra a month even worth it?
Yes. On a $5,000 balance at 24.99% with a $200 payment, $25 extra saves about 5 months and roughly $350 in interest. $50 saves about 9 months and $600. Small extras compound because they shrink next month's interest too.
Should I pay extra on the highest APR card first?
If you have several cards, yes — extra money on the highest APR card saves the most interest. That is the avalanche method. Our snowball vs avalanche calculator compares both approaches on your actual debts.
What if I get a windfall — bonus, refund, side income?
A lump sum works the same way, only bigger: it cuts the balance at once, which cuts every future month's interest. Apply it to the highest APR card first for the biggest saving.
Do I need to tell the card company the extra is for principal?
No. On a credit card, any payment above the interest is applied to principal automatically. Just make sure the payment posts before new interest accrues — paying earlier in the cycle helps slightly.
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