Enter Your Details
Example Data Table
| Balance | APR | Frequency | Regular payment | Extra recurring | Annual extra | Typical outcome |
|---|---|---|---|---|---|---|
| 15,000 | 18.5% | Monthly | 420 | 80 | 250 | Earlier payoff, lower interest, and a shorter schedule. |
| 8,500 | 14.9% | Biweekly | 210 | 40 | 0 | Faster reduction from more frequent payments. |
| 32,000 | 9.9% | Monthly | 650 | 0 | 500 | Annual boosts can cut total interest meaningfully. |
These rows are examples. Your results depend on your inputs.
Formula Used
Periodic interest rate
r = (APR ÷ 100) ÷ payments_per_year
For monthly payments, payments_per_year = 12. For biweekly, 26. For weekly, 52.
Amortization step
interest = balance × r
principal = payment − interest
new_balance = balance + interest − payment
Extra payments increase “payment,” reducing balance sooner and lowering future interest.
If your payment is less than or equal to the period’s interest, the balance may not decrease. The calculator warns you and may stop early based on your settings.
How to Use This Calculator
- Enter your balance, APR, and payment frequency.
- Set your regular payment to model the baseline plan.
- Add extra recurring, annual extra, and optional lump sum.
- Click Calculate to view summary and schedules.
- Download CSV for full schedules, or PDF for sharing.
Tip: Try a small recurring extra first. Even modest increases often produce noticeable interest savings.