Payment Tool
Estimate scheduled loan payments and total borrowing costs using flexible repayment frequencies, interest conventions and loan structures. Explore additional payments, fees and balloon balances, compare repayment scenarios, inspect interactive charts and amortisation schedules, and export results.
Balance over time
Payment breakdown
Amortisation schedule
| Period / date | Payment | Principal | Interest | Fees | Balance |
|---|
Estimates use fixed rates and an annual rate converted to the selected payment frequency. Payment dates are illustrative; actual lender rules, rounding and charges may vary. Interest-only loans repay the remaining principal in the final payment.
Table of Contents
Highlights
- Flexible payment frequencies and loan terms
- Nominal or effective annual interest rates
- Amortising and interest-only loan scenarios
- Interactive charts and detailed amortisation schedules
- Extra-payment comparisons and CSV or JSON exports
How Payment Tool Works?
The payment schedule starts with the amount borrowed plus any upfront fees added to the loan. For a fixed-rate principal-and-interest loan, the periodic interest rate is obtained from the entered annual rate and payment frequency. The regular repayment is calculated to reduce the balance towards any specified final balloon amount over the selected number of payment periods.
For a nominal annual rate, the periodic rate is:
For an effective annual rate, it is:
Here, r is the annual percentage entered as a decimal and m is payments per year. For an amortising loan with opening balance P, n scheduled payments and final target B, the regular principal-and-interest amount is:
When the rate is zero, the scheduled amount is (P − B) ÷ n. For interest-only loans, regular payments cover accrued interest and the unpaid principal is settled with the final payment. Each period's interest is calculated on the opening balance; principal payments and qualifying optional extras reduce that balance. The final instalment clears any balance still outstanding.
| Input or option | Effect on results |
|---|---|
| Loan amount and term | Set the initial borrowing and number of repayment periods. |
| Annual rate and rate type | Determine interest charged each period. |
| Repayment frequency | Monthly, fortnightly, weekly, twice monthly, quarterly or annually. |
| Extra periodic or one-off payments | May shorten repayment and reduce total interest. |
| Upfront and per-payment fees | Increase financed balance or cash cost, and periodic outgoings. |
| Balloon payment | Reduces scheduled amortising repayments, leaving a larger final settlement. |
Results include regular payment, total interest, total borrower cash outlay, estimated payoff date, interest saved versus no extras, a balance or cumulative-payment comparison chart, a payment breakdown, and a yearly or payment-by-payment amortisation schedule. The schedule can be exported as CSV, while summary CSV and results JSON exports are also available.
Practical Use Cases
Homebuyers: Compare monthly and fortnightly repayments for a mortgage, including additional contributions that could shorten the borrowing period.
Car buyers: Test vehicle finance with an end-of-term balloon and see how the larger final payment affects the repayment pattern.
Small-business owners: Budget equipment-loan repayments while including arrangement charges and recurring account fees.
Students and graduates: Explore how repayment length and interest rates affect the overall cost of a fixed-rate education loan.
Existing borrowers: Evaluate a one-off lump-sum repayment or recurring overpayments and compare estimated interest against the standard schedule.
Financial advisers: Review amortising versus interest-only repayment structures and share detailed repayment schedules through downloadable files.
Accuracy and Limitations
Figures are illustrative fixed-rate projections, not lender quotes. The model applies a constant rate per chosen payment period, rounds interest and repayments to cents, and uses approximate calendar spacing for weekly, fortnightly and twice-monthly dates. It does not model daily accrual, variable rates, compounding between instalments, late payments, tax, insurance, early-repayment penalties or lender-specific rules. Additional payments are applied without recasting scheduled instalments; interest-only loans settle remaining principal at maturity, and balloon amounts influence the scheduled amount but are cleared in the final payment. A dated one-off extra is applied on the first eligible scheduled payment before the last instalment, so a date after that point has no effect. Interest savings and payoff dates depend on these assumptions.
