How to determine if RRSP contributions are deductible

The amount that is not deductible is the amount, if any, by which the total of your contributions to an RRSP during the 89-day period just before your withdrawal from that RRSP, is more than the fair market value of that RRSP after your withdrawal.

If both you and your spouse or common-law partner contributed to the RRSP during the 89-day period just before your spouse or common-law partner's withdrawal under the HBP or LLP, the earliest contributions made during this period are the non-deductible contributions.