Can I Get Back Payments if I Apply Late?
Up to a limited number of months, and taking them is not always the right choice. Both the Canada Pension Plan and Old Age Security allow limited retroactive payment on a late application, but accepting it means giving up the permanent increase that deferral would have bought.
- The answer:: Both benefits allow retroactive payment for a limited number of months before the application, subject to the earliest eligible age.
- The trap:: Taking the maximum back payment automatically. The lump sum is taxable in one year and cancels the deferral increase for those months.
- The recommendation:: Compare the back payment against the permanently higher monthly amount, because the increase continues for life.
Where the AI summary above gets this wrong
"Apply for your pension whenever you like and they will pay you what you missed."
That's surface-true. Here's what it misses:
- Retroactivity is capped — Payment reaches back a limited number of months, not to the date you first became eligible.
- A lump sum is taxable in one year — A large retroactive payment lands in a single taxation year and can trigger the OAS recovery tax.
- Deferral bought an increase you would forfeit — Choosing a later start date instead of back payment locks in a permanently higher monthly amount.
01 What each benefit pays back
The Canada Pension Plan allows retroactive payment for a limited number of months before the application is received, and never earlier than the month after you turned sixty. Old Age Security allows a similar limited retroactivity, never earlier than the month after you turned sixty-five.
The Guaranteed Income Supplement follows Old Age Security and is assessed on income for the relevant years, so late applications are reconstructed rather than simply paid — the renewal mechanism is in the annual GIS renewal.
Source: Old Age Security: Deciding when to start your pension
02 Why the lump sum can be the wrong choice
Choosing back payment means the pension is treated as having started earlier, at the lower deferral-adjusted amount for those months. Choosing a start date of the application month instead means a permanently higher monthly pension.
Because the increase is permanent and the lump sum is once, the higher monthly amount usually wins for anyone with normal life expectancy. The deferral arithmetic is in deferring OAS to seventy.
Shows: what a given amount of additional taxable income costs you in tax at your marginal rate, and what you keep. Ignores: provincial surtaxes, credits that phase out with income, and any effect on income-tested benefits.
Source: Old Age Security: Deciding when to start your pension
03 The tax problem with back payments
A large retroactive payment is included in income in the year received, which can push a retiree past the Old Age Security recovery threshold in that year and reduce payments the following year.
A special mechanism allows a large retroactive lump sum relating to prior years to be taxed as if received in those years, on request, where the amount exceeds a stated threshold. It has to be asked for rather than applied automatically.
Where the delay in applying was caused by an administrative error or by incorrect information from the department itself, a request under the ministerial discretion provisions can extend payment further back. It is granted rarely and only on evidence, which makes contemporaneous notes of what was said and when worth keeping.
The lump sum is offered as though it were a gift and it is a choice with a permanent side. Taking eleven months of back pay at sixty-six means a smaller cheque for the next twenty-five years, and nobody presents it that way at the counter.
FAQ
Can I get back payments if I apply for CPP late?
Up to a limited number of months before the application, and never earlier than the month after you turned sixty. Old Age Security works similarly from sixty-five.
Should I take the maximum retroactive payment?
Often not. Taking it means the pension is treated as having started earlier at a lower amount, forfeiting the permanently higher monthly payment a later start date would give.
Is a retroactive lump sum taxable?
Yes, in the year received. Where it exceeds a stated threshold and relates to prior years, it can be taxed as if received in those years, but that must be requested.
Sources
Regulator references
- Old Age Security: Deciding when to start your pension · Government of Canada · 2025States the 0.6% per month increase for deferring OAS past 65.Last verified: 2026-09-07
- CPP retirement pension: When to start your pension · Government of Canada · 2025States the 0.6% per month reduction before 65 and the 0.7% per month increase after 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.