Include mortgage rate scenarios in the monthly budget
Compare assumed rates using the same loan and term, then place the payment differences alongside recurring spending.
Hold principal and term constant
Record principal, the remaining or new term and assumed rate. Change only the rate between scenarios to isolate the payment effect, checking the bank's actual rate basis separately.
Management, rates/Government rent, insurance and everyday spending remain outside the repayment table. List the required cash reserve and budget gap rather than treating a calculation as an approval or affordability decision.
Connect the payment difference to spending
Retain the assumptions for each scenario.
| Item | Record | Follow-up |
|---|---|---|
| Base | Amount, term and assumed rate | Retain inputs |
| Change | Alternative rate and payment | Compare monthly differences |
| Other spending | Known recurring costs | Avoid omissions and double counting |
| Buffer | Chosen cash reserve | Review the budget gap |
Illustration: recalculate at two assumed rates
Enter hypothetical 3% and 4% rates for the same HK$2 million principal and 25-year term. Add the calculated payment difference to the spending sheet; these rates are not current quotations or a forecast.
Keep the wider budget
- Scenario rates are not forecasts
- Other costs are included
- Cash reserves are planned separately