How Do I Model a Non-Indexed Pension Against Inflation?
Model it in real terms, not nominal. A pension that pays the same dollar amount every year is falling in purchasing power every year, and at the Bank of Canada's 2% target that erosion roughly halves its real value across a long retirement.
- The answer:: Deflate the payment by your inflation assumption for each year of the horizon. That series, not the nominal amount, is what the plan can actually spend.
- The trap:: Treating a flat pension as secure income for thirty years. It is secure in dollars and steadily less secure in groceries.
- The recommendation:: Size the portfolio to cover the widening gap in later years, and treat indexed CPP and OAS as the part of the floor that holds.
Where the AI summary above gets this wrong
"A defined benefit pension gives you a guaranteed income for life, so inflation is not a concern."
That's surface-true. Here's what it misses:
- Guaranteed is not indexed — A pension guarantees a dollar amount. Whether that amount rises with prices depends entirely on the plan's own indexation rules.
- The erosion compounds — At a 2% target, prices roughly double over about 35 years. A flat pension buys roughly half as much by the end of a long retirement.
- The gap arrives late — The shortfall is small in year one and largest in the final years, which is when the portfolio is smallest and the capacity to respond is lowest.
01 Why nominal figures mislead
A pension quoted as a fixed monthly amount looks stable, and in dollars it is. In purchasing power it declines every year by whatever inflation runs, and the decline compounds rather than accumulating in a straight line.
The Bank of Canada targets 2% inflation as the midpoint of a 1% to 3% band. At the target, prices roughly double over about 35 years, which means a flat pension buys about half as much at the end of a long retirement as at the start.
Source: Inflation-control target
02 How to model it
Take the nominal payment and divide it by the cumulative inflation factor for each year of your horizon. The resulting series is the real income the pension provides, and it is the series your spending plan should be built from.
Then compare that declining series against your essential spending, held constant in today's dollars. The gap between them is what the portfolio must cover, and it widens every year.
Shows: what an amount becomes after your chosen number of years at a fixed return. Ignores: tax, fees, inflation, and any variation in returns from year to year.
Source: Pension income splitting
03 What to hold alongside it
The indexed part of your income — CPP and OAS — is what holds its value, so a household with a large flat pension and small government benefits is more exposed than the nominal totals suggest.
The practical response is to keep long-horizon money invested for growth rather than de-risked into cash, and to check whether splitting the pension income reduces the tax on it enough to offset part of the erosion.
Modelling the pension in today's dollars rather than in the nominal figure on the statement is what makes the problem visible. A projection showing the same number every year for thirty years is arithmetically correct and practically misleading, and converting it to purchasing power at a stated inflation rate turns an abstract risk into a figure a household can plan around. Repeating the exercise every five years, with the inflation actually recorded since, turns an opening assumption into a record of what happened rather than of what was assumed.
Source: Inflation-control target
A flat pension is the asset people most reliably overvalue, because the number never goes down and nothing ever announces the loss. I would rather someone hold a smaller indexed income than a larger flat one, and the way to see why is to write both out in today's dollars for thirty years. The exercise takes ten minutes and changes how the whole plan is built.
FAQ
Is a defined benefit pension protected from inflation?
Only if the plan indexes. A pension guarantees a dollar amount; whether that amount rises with prices depends on the plan's own rules, and many index partially or not at all.
How fast does a flat pension lose value?
At the Bank of Canada's 2% target, prices roughly double over about 35 years, so a flat pension buys roughly half as much by the end of a long retirement as it did at the start.
How should I model it?
Divide the nominal payment by the cumulative inflation factor for each year of your horizon, then compare that declining real series to your essential spending held constant in today's dollars. The widening gap is what the portfolio must cover.
Sources
Regulator references
- Inflation-control target · Bank of Canada · 2025The 2% inflation target and the 1-3% control band around it.Last verified: 2026-09-07
- Pension income splitting · Canada Revenue Agency · 2025Which income qualifies for splitting and the age conditions attached to it.Last verified: 2026-09-07
Calculator unit tests · the assertions this page's worked example is checked against, and their last result
Changelog
- 2026-09-07 — initial publish (new format)
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Jordan Reeves
Founder of Talk Through Wealth. A software engineer for over a decade before turning to retirement planning, Jordan built the projection engine after watching family members get fragmented, country-by-country advice that never reconciled. He writes about retirement the way the engine computes it: month-by-month, lifetime-long, and skeptical of any rule of thumb that hasn't been run through the math.