Canada's SR&ED deadline is generous by the standards of the seven countries and absolutely firm. The claim is filed with the income tax return, and no later than 12 months after its filing due date. For a corporation whose return is due 6 months after year end, that is 18 months after the end of the tax year. There is no registration, no notification and, since 1 April 2026, an optional pre-claim approval. This page sets out the dates, what can be changed before the deadline, and a calendar for a 31 December year end.
Registration and notification
None. Optional pre-claim approval has been available since 1 April 2026, to have planned work assessed before you incur most of the cost, but it is a service, not a condition of claiming. Companies that do not use it simply file. Provincial credits likewise need no registration. Alberta and Quebec administer their own provincial incentives, with filing requirements outside the federal T2 schedules.
Claim deadline
| Item | Deadline | Late? |
|---|---|---|
| T2 corporation income tax return | 6 months after the end of the tax year | Late filing penalties; the return can still be filed |
| Balance of tax | 2 months after year end, or 3 months for qualifying CCPCs | Interest |
| Form T661 and Schedule 31 (the SR&ED reporting deadline) | 12 months after the filing due date of the return, so 18 months after year end for most corporations | No. A claim or part of a claim not filed by then is lost |
| Correcting a deficient T661 | By the reporting deadline | No |
| Carryback of unused credit | Request with the return for the year the credit arose | Within the normal reassessment period |
| Carryforward of unused credit | 20 years | Expires after 20 years |
| Records | 6 years from the end of the tax year | Not applicable |
The deadline attaches to each expenditure. An expenditure not shown on a T661 filed by the reporting deadline can never be added, even though the return itself can be reassessed for years afterwards. That is why late-discovered projects, and expenditures left off a filed claim, are the most common permanent losses in Canadian practice.
Amendments and late claims
Amending before the deadline. A claimant may file an amended Form T661 to add projects or expenditures before the reporting deadline, with an amended Schedule 31 and a request to reassess.
After the deadline. Expenditures cannot be added. Downward adjustments, for example to remove an ineligible project found in review, can be made at any time within the reassessment period. The CRA's policy recognises no extension for hardship, advisor error or late discovery.
Reassessment. The CRA can reassess within the normal reassessment period, 3 years from the notice of assessment for CCPCs and 4 years for other corporations, longer for misrepresentation. A claimant can request a reassessment downward within the same period.
Carryback and carryforward. Unused credits can be carried back 3 years or forward 20 years. A carryback is requested in the year the credit arises, and reduces tax already assessed for the earlier year.
Calendar for a typical year end
For a hypothetical CCPC, Chinook Software Inc., with a 31 December 2025 tax year.
| When | What happens |
|---|---|
| January to December 2025 | Work performed; time, tests and costs recorded by project |
| Early 2025 (optional) | Pre-claim approval application for the planned projects |
| By 31 March 2026 | Balance of tax due (3 months, as a qualifying CCPC) |
| By 30 June 2026 | T2 return due; T661 and Schedule 31 filed with it to start the refund clock |
| August to September 2026 | CRA processing: accepted as filed within the 60-day standard, or review within 180 days |
| By 30 June 2027 | SR&ED reporting deadline: last day to add projects or expenditures |
| To about mid 2029 | Normal reassessment period for a CCPC |
| To end of 2031 | Records retained |
Filing the T661 with the return rather than in the following year brings the refund forward by up to a year and leaves 12 months to amend if something was missed. Companies that file the T661 close to the reporting deadline have no room to cure an incomplete form, which is the single most common way a Canadian claim is lost outright.
Common questions
Our year ended 20 months ago. Can we still claim? No. The reporting deadline passed at 18 months.
We filed the T661 but missed a project. Can we add it? Yes, by amended T661, if the reporting deadline has not passed.
Does a CRA review extend the deadline? No. The reporting deadline is fixed by statute regardless of review.
Our return was filed late. Does the reporting deadline move? No. It is 12 months after the filing due date, not the actual filing date.
Can we carry a credit back to a year that is now closed? The carryback is requested in the year the credit arises and reassesses the earlier year, so it works even where that year would otherwise be beyond the normal reassessment period.
Related pages
Official sources
Educational content only, not tax advice. See the disclaimer.