🇨🇦 Canada · 5 min read · Published 2026-09-07 · Updated 2026-09-07

Written by Jordan Reeves · Editorial review: automated source and figure checks (how we check this)

Sources last verified: 2026-09-07

How Should I Build a Retirement Budget?

In three parts rather than one total. Fixed costs that continue whatever happens, discretionary spending that can genuinely flex, and lumpy irregular items that arrive every few years. The split matters more than the total, because only the middle part can absorb a bad market.

60-SECOND ANSWER

A retirement budget splits into fixed, discretionary and lumpy items, and only the discretionary part can flex in a downturn.

The answer:: Fixed costs, discretionary spending and irregular lumpy items, budgeted separately rather than as one annual figure.
The trap:: Averaging lumpy items into the annual number. A roof and a car do not arrive in equal instalments.
The recommendation:: Match guaranteed income to fixed costs, because that is the part that cannot be reduced when markets fall.

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Where the AI summary above gets this wrong

"You will need seventy percent of your pre-retirement income."

That's surface-true. Here's what it misses:

A replacement ratio is not a budget — It is a population average that ignores your mortgage status, your pension, and what you actually spend.
Fixed and flexible behave differently — Only discretionary spending can be reduced in a bad year, so the ratio between the two determines how much risk the plan can carry.
Lumpy items break annual averages — Roofs, vehicles and dental work arrive irregularly and are the most common reason a budget that looked fine fails.

→ See what a spending level requires

01 The three categories

Fixed costs are the ones that continue regardless: property tax, insurance, utilities, groceries, medications, condominium fees. Discretionary spending is travel, dining, gifts, hobbies and everything that can be reduced without changing where you live.

Lumpy items are irregular and large: a roof, a furnace, a vehicle, major dental work. They do not fit an annual budget and are the most common reason a plan that appeared adequate turns out not to be.

Source: Research on ageing and retirement income

02 Why the split matters more than the total

Only discretionary spending can flex. A retiree whose fixed costs consume all of their guaranteed income has no room to reduce spending in a bad market and must sell investments at a loss to continue.

Matching guaranteed income — CPP, OAS and any pension — to fixed costs is therefore the structural goal, because it means portfolio withdrawals fund only the part that can be cut. The rules for adjusting that part are in variable withdrawal rules.

WORKED EXAMPLE · Try the numbers

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.

Amount today ($)

Years

Return (%/yr)

Value at the end of the period

$57,435

$10,000 left for 30 years at 6% becomes $57,435 — the growth is 83% of the total.

Source: Research on ageing and retirement income

03 Handling the lumpy part

Irregular items are best funded from a separate reserve rather than smoothed into the annual figure, because averaging them produces a number that is wrong every single year: too high in most and far too low in the year the furnace fails.

A cash or short-bond reserve sized to the next few years of known replacements handles it without disturbing the portfolio — the same reserve serves the sequence-risk purpose in an emergency fund in retirement.

Building the first version from a year of actual bank and card statements rather than from estimates is what makes the exercise worth doing. Recalled spending is consistently lower than recorded spending, and a budget assembled from memory tends to omit precisely the irregular items the third category exists to hold.

Source: Inflation-control target

The replacement ratio survives because it lets someone give an answer without asking any questions. A person with a paid-off house and a bus pass needs a completely different number than a person with a mortgage and two cars, and the ratio treats them identically.