Make extra payments that shrink principal from one. See interest saved and payoff shortened fast. Download reports and schedules for clear decision support always.
Enter loan terms and extra payment choices. The calculator compares a standard schedule against your principal-reduction plan.
Sample inputs and outcomes to help you validate settings.
| Loan | Rate | Term | Frequency | Extra Each | Annual Extra | One-Time Extra | Typical Outcome |
|---|---|---|---|---|---|---|---|
| $250,000 | 6.500% | 30 years | Monthly | $150 | $1,000 | $5,000 at #13 | Fewer payments and lower total interest. |
| $120,000 | 5.250% | 15 years | Biweekly | $50 | $0 | $0 | Accelerates payoff with small consistent extras. |
| $60,000 | 0.000% | 5 years | Weekly | $25 | $0 | $500 at #10 | Principal falls quickly with no interest cost. |
Extra principal reduces the balance immediately, so the next period’s interest is computed on a smaller amount. On a $250,000 loan at 6.5% with monthly payments, adding $150 each payment plus a $1,000 annual extra can remove several years from the schedule. Biweekly payments increase the number of payment events per year, which accelerates principal turnover even with the same nominal rate.
Interest savings are driven by timing. A $5,000 one‑time extra in payment 13 attacks the balance early, when interest share is highest. If the same $5,000 is delayed to year five, the remaining balance is already lower, so the incremental savings typically shrink for most borrowers. Use the schedule preview to confirm when interest drops below principal and to spot the payoff inflection.
This calculator uses a fixed scheduled payment from the standard amortization formula, then layers extra principal on top. The baseline path holds extras at zero, while the extra plan applies your per‑payment, annual, and lump‑sum choices together. The final payment is capped so the balance never becomes negative. Export the CSV to audit totals, reconcile statements, and share scenarios with lenders over time accurately.
Frequency changes cash‑flow rhythm. Monthly makes budgeting predictable, while weekly or biweekly can align with payroll and shorten the time between interest calculations. For example, a 15‑year loan at 5.25% with $50 extra biweekly often pays off meaningfully earlier than the same extra applied monthly, because the balance is reduced more frequently. Always verify your lender credits extras to principal in many budgets.
Use results to set a target and track progress. Start with an extra amount you can sustain, then test an annual extra tied to bonuses or tax refunds. Compare “payments saved” against your goal date and confirm interest saved. If your rate is 0%, extras reduce duration, not cost. Re‑run scenarios when rates, income, or priorities change, and update your plan to stay on course.
Yes. The scheduled payment is computed from your loan terms. Extra amounts are added separately and applied to principal, so payoff can shorten and interest can fall.
Use your note rate as a nominal annual percent. The calculator divides it by payments per year to get the per‑period rate used in the schedule.
Enter a start date to estimate payment dates and payoff date. Without it, the schedule still computes payments and totals, but dates display as dashes.
Set extra each payment and the start payment number. You can also add a once‑per‑year extra on a chosen payment number and a one‑time lump sum on any payment.
Most servicers apply verified extra funds to principal, but rules vary. Confirm how to label the payment, whether there is a prepayment penalty, and how escrow is handled.
The CSV exports every row of the schedule. The PDF exports a compact summary you can share, print, or archive with your loan documents.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.