Same Purchase, Different Payment Method — Very Different Cost
When you put a big purchase on a credit card, how you pay it off changes the real cost far more than most people expect. Pay in full and there's no interest — you pay exactly the sticker price. Choose an interest-bearing installment plan and you'll pay extra based on the term and APR. But carrying a revolving balance, where you pay only a small minimum percentage each month and let the rest roll over, is usually the most expensive path: the entire remaining balance keeps accruing interest at a steep APR, often 20-29%, and the slower you pay it down, the more that interest compounds. This calculator lines up the total cost and interest for all three side by side.
How It's Calculated
| Method | Calculation |
|---|---|
| Pay in full | Purchase amount (no interest) |
| Installment plan | Declining-balance interest approximation + principal |
| Revolving balance | Fixed % of balance paid monthly + accrued interest on the rest |
Actual APRs and terms vary by issuer, your credit profile, and any promotional offers, and revolving accounts also have contractual minimum payment rules that can differ from a flat percentage. A revolving balance is especially easy to lose track of, since the payment keeps rolling forward and the balance can feel smaller than it really is. For large purchases, paying in full or using a 0% promotional installment plan keeps total cost lowest — treat revolving as a short-term, last-resort option and pay it down as fast as possible. This tool is a simplified estimate; check your card issuer's terms for exact figures.
Frequently Asked Questions
The full remaining balance keeps accruing high APR interest while only a small minimum percentage goes to principal, so interest compounds and total cost snowballs.
Yes — with no interest, total cost equals the purchase price. Just enter 0 for the installment APR to model a 0% offer.
※ Simplified interest estimate; actual card issuer statements may differ.