Calculator inputs
Example data table
Use these sample values to see how the stress test behaves.
| Sample balance | Rate | Remaining | Extension | Stress | Fee | Typical insight |
|---|---|---|---|---|---|---|
| 2,500,000 | 19.50% | 48 months | 12 months | +2.00% | 15,000 | Extension can reduce EMI, but increases total interest. |
| 1,200,000 | 16.00% | 24 months | 24 months | +3.00% | 8,000 | Stress rates may offset the relief from longer tenure. |
| 5,000,000 | 21.25% | 60 months | 18 months | +1.50% | 30,000 | Fees matter when comparing total cost across scenarios. |
Formula used
The monthly instalment is calculated using the standard amortizing loan payment formula:
- P is the remaining loan balance (principal).
- r is the monthly interest rate = annual_rate / 12 / 100.
- n is the number of remaining monthly payments.
For a 0% rate, the payment becomes P / n.
How to use this calculator
- Enter your remaining loan balance, current rate, and remaining tenure.
- Add the desired extension and a stress rate increase.
- Optionally include a one-time fee and extra monthly payments.
- Provide income and other debts to see affordability ratios.
- Press Submit to compare scenarios and review total cost.
- Use Download CSV or PDF to store and share outputs.
These results are estimates for planning and stress testing.
Payment relief versus interest drag
Extending tenure lowers the instalment because the balance is spread over more months. Payment falls as n rises, but total interest usually increases because interest accrues longer. A 12‑month extension on a 48‑month plan can ease cash flow while raising lifetime cost. Use the comparison table to weigh monthly relief against total interest and total cost. Lower payments can help, but long-term costs still accumulate.
Stress rate coverage for budget planning
A stress test adds a margin to the current annual rate to model repricing shocks. If the rate rises by 2.00 percentage points, the instalment increases, especially on larger balances. Treat “Extension + Shock” as a conservative budget line. If that payment fits comfortably, your plan is better protected from market moves. Use the shock rate that matches your risk horizon.
Fee break-even and decision thresholds
One-time fees change the economics of extending tenure. Add the fee to total outflow, then compare it to the monthly payment reduction. If an extension saves 8,000 per month, a 15,000 fee is recovered in about two months. If the saving is 1,000, payback is about fifteen months, and added interest may dominate. Use payback and total cost together. If fees are negotiable, test both quoted and reduced.
Affordability checks with debt-to-income
Income and existing obligations translate repayments into affordability. Debt-to-income is estimated as (other debt + instalment) ÷ income. Track the base ratio and the stressed ratio together. A modest payment shift can materially reduce flexibility when income is tight or expenses are volatile. Record the ratio before choosing refinance or extension options.
Reporting, audit trail, and scenario discipline
Scenario discipline improves decisions. Keep inputs consistent: the same balance, tenure definition, and extra payment across runs. Export CSV for review and save a PDF for files. When comparing options, focus on monthly payment, total interest, and total cost including fees. This structure supports clear approvals. Repeat quarterly to keep the plan aligned with reality.
FAQs
What does “Extension + Shock” represent?
It combines a longer tenure with a higher stressed rate. Use it as a conservative case to see the maximum likely payment and total cost if you extend and rates move against you.
Why can total interest rise when payment falls?
A longer tenure reduces the instalment, but you pay interest for more months. Even with smaller payments, the added time can increase cumulative interest and raise total cost, especially at higher rates.
How is the stress rate applied?
The stress input is added in percentage points to your current annual rate. For example, 19.50% plus 2.00% becomes 21.50%, and the payment is recalculated using the same balance and tenure.
What should I enter for remaining tenure?
Enter the months or years left on your current repayment plan, not the original term. If you only know the maturity date, estimate the remaining months to that date for a consistent comparison.
How does extra monthly payment affect the test?
Extra monthly payments are added to each scenario’s instalment. They can reduce interest and shorten the effective payoff time in the schedule view, helping you test whether small overpayments improve resilience under stress.
Can I use the exports for sharing?
Yes. CSV is useful for spreadsheets and sensitivity checks, while PDF is better for approvals, client files, and printing. Always label the assumptions used, such as tenure, fee, and stressed rate.