What an RRSP deduction actually buys you

Every February, Canadians are told to make an RRSP contribution and get a refund. The refund is real, and it is not a reward — it is the government lending you its share of that dollar until you take the money out.

The mechanic: a deduction moves income, it does not erase it

When you contribute to an RRSP, you subtract the contribution from your taxable income for the year. Less taxable income means less tax, and if your employer already withheld tax on that income, the difference comes back as a refund.

What you have actually done is move that income to a later year. The contribution goes in untaxed, grows untaxed, and is taxed in full when it comes out — not just the growth, the whole withdrawal. There is no partial exemption and no capital-gains treatment inside an RRSP. A dollar withdrawn is a dollar of ordinary income.

So the RRSP is a bet with exactly two variables: the rate you avoid today and the rate you pay later. Everything else — how well the investments do, how long you hold them — is identical to what would have happened in a TFSA. The tax-free growth is not the RRSP's advantage; the TFSA has that too. The rate gap is the advantage.

Priya deducts at 37%, and withdraws at 20%

Priya — 54, Ontario, single. $118,000 salary, $410,000 in her RRSP and $88,000 in her TFSA, planning to retire at 63.

Priya earns $118,000 and puts $11,800 into her RRSP each year. Her marginal rate — the rate on her next dollar — is 37.2%, combining federal and Ontario tax. So that contribution defers $4,385 of tax this year.

The interesting number is the other one. Running her plan forward — she retires at 63, lives on her accounts plus CPP and OAS — her marginal rate at 70 comes out at 20.1%. The same $11,800, withdrawn at that rate, costs her about $2,366.

Tax on $11,800: $4,385 deferred today at 37.2%, versus about $2,366 paid later at 20.1%. — The same dollars, taxed at two different rates. The gap between the bars is what the deferral is worth — before counting the growth on the deferred tax itself.

That is the deferral working as intended: she skips tax at a high rate while earning and pays it at a lower one while retired. And because the deferred tax stays invested in the meantime, it compounds for her rather than for the government.

The same mechanism has a second face, though. By 72 — the age mandatory RRIF withdrawals begin — her RRSP is projected at $849,214. That is a large deferred tax bill arriving on a schedule she does not control, which is a problem this series comes back to more than once.

When the trade goes the other way

The deferral is only worth something if the later rate is lower. Several ordinary situations flip it:

A low-income year now and a high-income career later — an early-career contribution can be deducted at a lower rate than it will eventually be taxed at.
A very large RRSP, where mandatory withdrawals in your seventies push income above what you actually spend, and above thresholds like the OAS recovery tax.
A modest retirement income where the Guaranteed Income Supplement is in play. GIS is reduced as other income rises, which can make an RRSP withdrawal cost far more than its headline tax rate suggests.

None of these make an RRSP a mistake. They make it a calculation — one that depends on your own two rates rather than on a rule of thumb.

The projection reports your marginal rate in every year of your plan — working and retired — so you can see your own version of the gap in this episode rather than an assumed one.

See your two rates

Next: the TFSA, where "tax-free" turns out to be the least interesting thing about it.

GlidePathEngine is an educational planning tool — not financial, investment, tax, or legal advice.