SR&ED filing deadlines: the 18-month rule
The SR&ED reporting deadline is one of the few truly hard deadlines in tax. Miss it and the credit is gone — there's no late filing for the prescribed SR&ED information.
Here's how the deadline works and how to find yours.
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The 18-month rule
Your SR&ED reporting deadline is 12 months after your T2 filing-due date — which works out to 18 months after the end of the fiscal year in which you did the work. The prescribed SR&ED information (your T661 narratives and key amounts) must be filed by that date.
Why it's effectively a hard cutoff
Unlike many filing obligations, the SR&ED reporting deadline generally cannot be extended. If the prescribed information isn't filed in time, the expenditures can't be included in the SR&ED pool for that year — the claim is simply lost.
A worked example
Say your fiscal year ends December 31, 2025. Your T2 is due six months later (June 30, 2026), and your SR&ED reporting deadline is 12 months after that — June 30, 2027. That's 18 months after the December 31, 2025 year-end.
Why firms miss it
The usual culprit is treating SR&ED as an afterthought to the tax return rather than a project of its own. Because the window is long, it's easy to defer — and then run out of runway to gather evidence and write narratives. Start early, and keep your documentation current throughout the year.
Frequently asked questions
Generally 18 months after the end of the fiscal year in which the work was done (12 months after your T2 filing-due date).
No — the SR&ED reporting deadline is effectively firm. The prescribed information must be filed by the deadline or the claim for that year is lost.
The SR&ED expenditures for that year can no longer be claimed. The year is closed for SR&ED purposes.
Take your fiscal year-end, add six months (your T2 due date), then add another twelve months. That date is your SR&ED reporting deadline.
You can adjust a claim, but only within the same reporting-deadline window. After the deadline you can't add new SR&ED expenditures for that year.
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This guide is general information, not tax advice — SR&ED rules, rates and limits change, so confirm the current figures with the CRA or your advisor before you file.