Seniors and students

Your unused RRSP contributions can be found by;

Logging in to your CRA My Account or My CRA mobile app.
Calling the Tax Information Phone Service (TIPS) line 1-800-267-6999
Or on your latest notice of assessment or notice of reassessment.

https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/rrsps-related-plans/contribu...