Guide · Tax year 2026
How RRSP contributions affect income tax
An RRSP contribution is a deduction, not a credit. It comes off your income before tax is calculated, which means it is worth the rates it actually spans rather than a single headline number.
What a deduction does
A non-refundable credit reduces the tax you owe by a fixed percentage of the amount claimed, the same percentage for everyone. A deduction reduces the income the tax is calculated on, so its value depends on where that income sits. Deduct $15,000 from a $120,000 salary and you remove the top $15,000 of that salary from the calculation, whatever rates that slice happened to be taxed at.
It does not change your pension or employment insurance contributions. Those are charged on gross earnings and no deduction reaches them. The saving is income tax only, federal and provincial.
It saves less than your top marginal rate
The commonest overestimate is to multiply the contribution by the marginal rate. That is right only if the whole contribution sits inside one band. As soon as it crosses a bracket boundary, a surtax threshold or a credit phase-out, the lower part of the contribution is saving tax at a lower rate.
| Province | Marginal rate at $120,000 | Tax saved | Saved per dollar | Net cost of the contribution |
|---|---|---|---|---|
| Ontario | 43.4% | $5,290.41 | 35.3% | $9,709.59 |
| Alberta | 36.0% | $4,676.01 | 31.2% | $10,323.99 |
| British Columbia | 38.3% | $4,808.73 | 32.1% | $10,191.27 |
| Quebec | 45.7% | $5,939.12 | 39.6% | $9,060.88 |
In Ontario the marginal rate at $120,000 is 43.4%, but the $15,000 contribution returns 35.3% of itself, not 43.4%. The gap is not small: it is $1,221.09 of imagined refund. The reason is that the top of the deduction unwinds the Ontario surtax and the higher federal bracket, and the bottom of it does not.
Sometimes it saves more
The effect runs both ways, because a deduction can drop your income through a step that a small raise never touches. A $10,000 contribution on a $75,000 Ontario salary saves $3,115.00, which is 31.1% of the contribution against a marginal rate of 28.5% measured upward from that salary. Part of the difference is the Ontario health premium: it falls from $750.00 to $600.00, a further $150.00 that no rate table would show you.
This is why the RRSP calculator computes two complete years rather than multiplying by a rate. It is the same method used for a bonus, for the same reason.
Refund now or refund later
If you contribute through payroll, your employer reduces the income it withholds tax on, so the benefit arrives in each pay cheque and there is no refund to wait for. If you contribute yourself, the full tax is withheld during the year and the deduction is claimed on your return, so the same money comes back months later. The total is the same either way. Only the timing differs.
You can also contribute in one year and claim the deduction in a later one. The contribution room is used when you contribute, but the deduction can be carried forward, which is worth knowing if you expect to be in a higher bracket soon.
What this is and is not
- The tax is deferred, not cancelled. Money coming out of an RRSP is ordinary income in the year it comes out. The bet is that your rate then is lower than your rate now. That is a personal question and this site does not answer it.
- Contribution room is not modelled here. Room is broadly eighteen percent of the previous year earned income up to an annual dollar limit the Canada Revenue Agency publishes, reduced by any pension adjustment and increased by unused room carried forward. Your notice of assessment states your figure; nothing on this site knows it.
- Income-tested benefits are not modelled either. Reducing net income can raise a benefit calculated on your return. That is a genuine effect and it is outside the scope of a payroll calculation.
- A TFSA works the other way. No deduction going in, nothing taxable coming out. Which is better depends on rates now against rates later, which is again not a question a calculator settles.
Related
- Marginal versus average
- How bonuses are taxed
- Gross pay versus net pay
- RRSP tax savings calculator
- Salary after tax calculator
- All guides
Sources
- Current year tax rates and income brackets (2026) · Canada Revenue Agency · checked
- CPP contribution rates, maximums and exemptions, 2026 · Canada Revenue Agency · checked
- T4032 Payroll Deductions Tables, January 2026 · Canada Revenue Agency · checked
- Canada Employment Insurance Commission sets the 2026 Employment Insurance premium rate · Employment and Social Development Canada · checked
Reviewed 2026-08-18