Credit Card Interest Savings Calculator
This calculator shows exactly how much interest you save by paying a fixed higher amount instead of the shrinking minimum payment. Enter your balance, APR, minimum payment percentage and floor, and your proposed higher fixed payment. The calculator runs both scenarios month by month and computes the total interest paid in each case. The difference is your interest savings. Even a modest increase in monthly payment can cut years off your payoff timeline and save hundreds or thousands of dollars.
Interest savings formula
Interest saved = Total interest (min payments) - Total interest (fixed payment). Run each scenario monthly: balance = balance + balance*(APR/12/100) - payment.
For minimum payments: payment = max(balance * minRate%, floor), reducing each month as balance falls. For fixed payment: constant amount each month until balance reaches zero.
The real cost of credit card interest
With a typical 20% APR credit card, the monthly interest rate is about 1.67%. On a $3,000 balance, that is $50 per month in interest alone. A 2% minimum payment is $60, meaning only $10 per month reduces the principal. At that pace, payoff takes decades. Setting a fixed payment of $150 cuts the payoff to about 24 months and saves a substantial amount in interest compared to the minimum-only approach.
Frequently asked questions
How much interest can I save by paying more each month?
Even small increases above the minimum payment can save large amounts of interest. On a $3,000 balance at 20% APR, paying $150 per month instead of the 2% minimum saves thousands of dollars in interest and reduces payoff time from over 20 years to under 2 years.
What is a fixed payment versus a minimum payment?
A fixed payment stays the same every month (e.g., $150). A minimum payment decreases as your balance decreases (e.g., 2% of balance). Fixed payments pay off debt far faster because they apply more principal each month.
How does this calculator compute interest savings?
It runs two simulations side by side: one paying only the minimum (percentage of balance), and one paying the higher fixed amount you enter. It computes total interest for each scenario and shows the difference.
Should I pay off my credit card or invest?
If your credit card APR is higher than your expected investment return (after tax), paying off the card is mathematically superior. Most credit cards charge 18 to 25% APR, which exceeds typical stock market returns net of taxes.
Does paying more than the minimum affect my credit score?
Yes, positively. Lower credit utilization (balance-to-limit ratio) is a major factor in credit scores. Paying down your balance improves utilization and typically raises your score. On-time payments also build positive payment history.
Official sources
- CFPB: Credit Cards.
- CARD Act of 2009, Pub. L. 111-24: Full text (GovInfo).
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.