What an extra payment actually does

A worked example

Say you owe $6,000 on a card at 22% APR and pay $200 a month.

The first month’s interest is $110. The question is what another $100 a month changes.

The extra $100 a month clears the card 18 months sooner and saves $1,248 in interest.

Across the shorter payoff you put in $2,600 of extra payments. Almost half of that comes back as interest you never pay.

These figures come from the same math as the calculator above, so the two always agree.

How this calculator works

You enter a balance, an APR, your monthly payment, and an extra amount you can add.

Each month it adds interest at the APR divided by 12, subtracts your payment, and repeats until the balance reaches zero. It runs that twice. Once at your current payment, once with the extra added.

The gap between the two runs is the interest saved and the months saved.

If your payment does not cover the first month’s interest, the balance never falls. The calculator tells you so instead of printing a date that never arrives.

It assumes a fixed payment, no new charges, and a steady rate. Most issuers charge interest on a daily balance, so your statement can differ by a few dollars.

Why a small extra goes so far

Interest is charged on the balance you still owe. Every extra dollar cuts that balance today, so next month’s interest is smaller too.

That saving repeats every month until the card is gone. A small, steady extra adds up faster than its dollar amount suggests.

Steady is the part that matters. A single extra payment helps a little. The same extra every month moves the payoff date.

Questions people ask about paying off debt faster

Is it better to pay extra every month or make one large payment later?

For total interest, sooner wins. A dollar paid this month stops collecting interest this month. For most budgets a steady monthly extra is the version that lasts, and lasting is what gets a card to zero.

Should I pay extra on debt or build savings first?

Most people do better with a small emergency fund first. Without one, the next car repair lands on the card you are paying down. After that, extra dollars on a card charging over 20% save more than a savings account earns.

Does my extra payment go to the balance?

Yes. Everything above the month’s interest and fees reduces what you owe. If one card carries balances at different rates, federal rules send the amount above the minimum to the highest-rate balance first.

What if I cannot find any extra money?

Then the payment you have is the plan, and the date on the calculator is the honest answer. If that date is years away or never arrives, a lower rate matters more than a bigger payment. To price a lower rate, try theconsolidation loan calculator.

Will paying off a card early hurt my credit?

No. Paying a card down lowers your credit utilization, which usually helps. Closing the account afterward is a separate choice. It removes that card’s limit from your available credit, and that can raise utilization on the cards you keep.