If after receiving your statement from CRA, you find that you've made contributions in excess of your contribution limit, there is a "safety net". Over-contributions can remain in your plan without penalty as long as the excess balance is $2,000 or less. (If your over-contribution exceeds $2,000, you may be assessed a penalty of 1% per month on the excess amount.) While you won't get a tax deduction for any over-contribution in the year it is made, you can claim it as part of your contribution limit in subsequent years.