Part 1 · SR&ED basics
Deadlines and evidence
You usually have 18 months after your tax year ends to claim. Good records made at the time are what make a claim hold up.
The filing deadline
The claim (Form T661 and the credit schedule) is due 12 months after your corporate tax return is due. For most corporations that is 18 months after the end of the tax year. Miss it and the credit for that year is lost; the CRA does not extend it.
| Tax year ends | Claim due by |
|---|---|
| December 31, 2025 | June 30, 2027 |
| March 31, 2026 | September 30, 2027 |
| June 30, 2026 | December 31, 2027 |
The app knows your fiscal year end from Settings, SR&ED profile, so a Past assessment can cover work that is still inside the window.
Evidence the CRA looks for
- What you were trying to do, and why the answer was not known.
- What you tried, in order, and what happened each time (including what failed).
- Who did the work, and roughly how much of their time it took.
- Records made at the time: commits, tickets, test results, notes and design docs.
Your commits are evidence
Connect GitHub and the app links commits to people and to the SR&ED work they support. That turns everyday work into a dated record.
If the CRA reviews your claim
A reviewer may ask to talk to the people who did the work and to see the records. A claim built from real commits and clear project notes is much easier to support. Print or save every assessment so the record stays with your files.
Sources
This guide helps you prepare. It is not tax advice. Have your SR&ED preparer review your claim before you file.