Indexed against conventional, side by side
The spread between the cheapest and most expensive path is $281,917 over 30 years — Conventional Fixed wins under these assumptions.
Lowest total cost
Scenario AConventional Fixed
6.25% nominal · no indexation
$2,770.73
Fixed Monthly Payment
$997,462
Total Repayment
$2,771
Final Payment
$547,462
Total Interest
$0
Indexation Added
Scenario B
Indexed Bounded
4.50% nominal · 2.00% indexation
$2,283.85
First Payment (Month 1)
$1,121,972
Total Repayment
$4,130
Final Payment
$466,746
Total Interest
$205,226
Indexation Added
Scenario C
Indexed Unbounded
4.50% nominal · 2.80% indexation
$2,285.34
First Payment (Month 1)
$1,279,379
Total Repayment
$5,221
Final Payment
$514,195
Total Interest
$315,184
Indexation Added
Repayment Trajectory
Average monthly payment per year. Indexed products start lower and climb with the index; the bounded product stops climbing once the ceiling binds.
Conventional
Indexed (Bounded)
Indexed (Unbounded)
Year 1Year 15Year 30
Conventional Fixed
$677,406
Total cost in today's money · peak payment $2,771
Indexed Bounded
$731,495
Total cost in today's money · peak payment $4,130
Indexed Unbounded
$820,830
Total cost in today's money · peak payment $5,221
Amortization Schedule
| Month | Principal Owed | Interest | CPI Adj. | Payment |
|---|---|---|---|---|
| 001 | $450,000.00 | $1,690.29 | +$743.21 | $2,283.85 |
| 002 | $450,149.65 | $1,690.85 | +$743.46 | $2,287.62 |
| 003 | $450,296.34 | $1,691.40 | +$743.70 | $2,291.40 |
| 004 | $450,440.04 | $1,691.94 | +$743.94 | $2,295.18 |
| 005 | $450,580.73 | $1,692.47 | +$744.17 | $2,298.97 |
| 006 | $450,718.39 | $1,692.99 | +$744.40 | $2,302.77 |
| 007 | $450,853.01 | $1,693.49 | +$744.62 | $2,306.58 |
| 008 | $450,984.54 | $1,693.99 | +$744.84 | $2,310.38 |
| 009 | $451,112.98 | $1,694.47 | +$745.05 | $2,314.20 |
| 010 | $451,238.30 | $1,694.94 | +$745.26 | $2,318.02 |
| 011 | $451,360.47 | $1,695.40 | +$745.46 | $2,321.85 |
| 012 | $451,479.48 | $1,695.84 | +$745.66 | $2,325.69 |
Illustrative modelling only. Real indexed mortgages index on published CPI prints with a lag, and caps may apply per period rather than annually. Confirm terms with your lender before deciding.