Can I roll my entire retiring allowance into my RRSP without using up regular contribution room?

Not necessarily the entire amount — this is a genuinely common misunderstanding about how the retiring allowance rollover works. There is a special rule that lets you transfer part of a retiring allowance directly into your RRSP without using up your regular annual RRSP contribution room, which is a real and valuable benefit. But that special rollover eligibility is limited, not unlimited — it's tied specifically to your years of service before a particular cutoff date, and the eligible amount depends on your own service history rather than applying automatically to the full size of whatever retiring allowance you receive.

If your retiring allowance is larger than your eligible rollover amount, the excess doesn't get the same treatment — it would either be paid to you directly, subject to ordinary withholding, or would need to use up your regular RRSP contribution room like any other RRSP contribution, if you have room available and choose to contribute it that way.

Because the eligible amount is specific to your years of service and the applicable cutoff rules, don't assume your whole payment qualifies for this special treatment. Confirm your actual eligible rollover amount before deciding how to handle the rest of the payment, since the difference can meaningfully affect both your immediate tax bill and your RRSP room going forward.