Start with the identity nobody mentions

If your marginal tax rate is the same when you contribute and when you withdraw, a TFSA and an RRSP produce exactly the same after-tax result. Not approximately — identically. The algebra is symmetric.

That single fact reframes the whole question. You are not choosing between a better and a worse account. You are making a bet on the direction of your own tax rate.

The actual rule

  • Marginal rate higher now than in retirement? RRSP. You deduct at the high rate and withdraw at the low one, and the gap is your profit.
  • Marginal rate lower now than in retirement? TFSA. Pay tax at today's low rate and never pay again.
  • About the same? Use the TFSA for flexibility — withdrawals are unrestricted and restore contribution room the following year.

For someone early in their career, the TFSA usually wins: your income is low now and probably will not be lower later. For someone at peak earnings, the RRSP usually wins.

The factor most comparisons omit

Your marginal rate in retirement is not just the income tax bracket. RRSP and RRIF withdrawals are taxable income, and taxable income determines eligibility for income-tested benefits — the Guaranteed Income Supplement most sharply, and Old Age Security through the recovery tax.

For a lower-income retiree, the effective marginal rate on an RRSP withdrawal can be dramatically higher than the nominal bracket once benefit reduction is included. TFSA withdrawals are not income and do not enter any of those calculations.

This is why the RRSP is often the wrong account for someone who will rely substantially on GIS in retirement, even though their working-life bracket suggests otherwise.

Contribution room works differently

TFSA room accrues from the year you turn 18 and is not tied to income. Withdraw and the amount is added back to your room — but only on January 1 of the following year. Re-contributing in the same calendar year is the most common cause of TFSA over-contribution penalties.

RRSP room is earned: a percentage of the prior year's earned income, up to an annual maximum, reduced by any pension adjustment. Unused room carries forward indefinitely. Your exact room is on your CRA Notice of Assessment — use that number, not an estimate.

The employer match beats both

If your employer matches group RRSP contributions, that match is an immediate return no market provides. Take it in full before optimising anything else on this page.

A note on what goes inside

Neither account is an investment. Both are wrappers, and both can hold cash earning nothing. Someone with a TFSA full of a savings account is getting the tax shelter with none of the growth it exists to shelter.

What to do with this

  1. Capture any employer match first.
  2. Estimate your marginal rate now and your realistic taxable income in retirement, including benefit clawbacks.
  3. Check your actual room on your Notice of Assessment before contributing.
  4. Decide what the money is invested in — the wrapper is only half the decision.

Dollar limits and rates in this article change over time. The linked sources are the authoritative versions — check them before acting on anything here.