Calculator Inputs
Example Data Table
Use these scenarios to validate your inputs and outputs.
| Scenario | Start | APR | Frequency | Payment | Extra | Payments | Estimated remaining |
|---|---|---|---|---|---|---|---|
| Standard | USD 10,000 | 8.50% | Monthly | USD 350 | USD 0 | 36 | Varies by settings |
| With extra | USD 10,000 | 8.50% | Monthly | USD 350 | USD 50 | 24 | Lower than Standard |
| Fee-heavy | USD 10,000 | 8.50% | Monthly | USD 350 | USD 0 | 36 | Higher with recurring fees |
Formula Used
Each period updates the balance in this order:
- Interest is computed on the starting balance.
- Fees (if any) are added to the balance.
- Payments reduce the updated balance, never below zero.
How to Use This Calculator
- Enter your starting balance and your annual rate.
- Choose a payment frequency and the number of payments.
- Add fees, extra payments, or a lump sum if needed.
- Click Calculate to see results above the form.
- Download your schedule as CSV or PDF for records.
Balance trajectory under fixed payments
With a starting balance of 10,000 and a monthly payment of 350, the calculator builds a period-by-period schedule. On a periodic basis at 8.50% APR, the first month’s interest is about 70.83 (10,000 × 0.085 ÷ 12). The ending balance after the first payment is therefore near 9,720, before any fees or extra payments.
Daily versus periodic interest sensitivity
Choosing daily interest uses APR/365 multiplied by days between payments. A 31‑day gap produces slightly more interest than a 28‑day gap, even with the same APR. This matters for custom intervals, biweekly plans, and irregular payment dates. The schedule includes “days elapsed” so you can audit why two similar months produce different interest amounts.
Impact of extra and lump‑sum payments
Adding 50 extra per payment increases reduction speed without changing APR. Over 36 monthly payments, that extra 1,800 can shorten payoff time and lower cumulative interest. A one‑time lump sum, such as 1,000 at payment 12, creates an immediate step down in the balance curve. The chart highlights these inflection points clearly.
Fees and real cost measurement
Upfront and recurring fees change the effective cost of borrowing. If a 200 upfront fee is added to the balance, you pay interest on it over time. A recurring fee of 5 across 36 payments adds 180 directly, and may also increase interest because fees are applied before payments. Comparing “fees paid” to “interest paid” helps quantify total friction.
Scenario comparison and decision support
Use the exportable schedule to compare alternatives: higher payment, extra payment, lower APR, or fewer payments. Track remaining balance, cumulative paid, and principal components per period. For budgeting, focus on the last payment date and remaining balance after your chosen number of payments. For optimization, aim for higher principal share earlier. When evaluating debt versus savings goals, test payment frequencies. Weekly payments reduce average balance earlier, often trimming interest. The calculator’s stacked bars separate interest, fees, and principal, making trade‑offs visible for stakeholders and approvals.
FAQs
What does the remaining balance figure show?
It is the unpaid amount after applying interest, fees, and your scheduled payments through the processed periods. If the plan pays off early, remaining balance becomes zero and the schedule stops.
How are upfront and recurring fees treated?
Upfront fees can be financed by adding them to the starting balance, or kept separate. Recurring fees are added each period before payments, so they can increase both total fees paid and interest over time.
What is the difference between daily and periodic interest?
Periodic interest applies a rate per payment based on your selected frequency. Daily interest uses APR/365 multiplied by the actual days between payment dates, which makes month length and custom intervals more noticeable.
Why did my schedule end before the number of payments?
If your payment plus extras and a lump sum reduce the balance to zero, the calculator stops generating additional rows. That indicates an early payoff and a shorter effective term than planned.
Can I model irregular or accelerated payments?
Yes. Use Custom frequency for fixed day spacing, add Extra payment for each period, and apply a Lump sum on a chosen payment number. For truly irregular dates, rerun the calculator with different start dates and intervals.
How do the CSV and PDF downloads work?
After you calculate, the page stores your latest results in a session and generates downloads on request. CSV includes all schedule rows for spreadsheets, while PDF produces a clean one‑page summary suitable for sharing.