Credit & Debt
Total interest paid
Everything paid beyond the original balance is interest. Compare two payment sizes here — the difference is startling.
The Formula
Total Interest = (P x n) - B
Everything paid beyond the original balance is interest. Compare two payment sizes here — the difference is startling.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| I | Total interest | currency | Cumulative interest across the whole payoff period, not per month. |
What Each Symbol Means
Icurrency
Total interest
Cumulative interest across the whole payoff period, not per month.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate credit card payoff time page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate Credit Card Payoff Time, filed under Finance. Every number the guide produces comes from substituting into this one line.