The reason for using 15% for making RRSP contributions is to
include your approximate tax savings in your contributions.
Your family income is $70,000 per year. If
you are using your pay-yourself-first money to make extra payments on
your debt, you would use 10%, or $7,000.
If you want to contribute your pay-yourself-first
money to your RRSP, you would contribute 15%, or $10,500. If you
are in a 30% tax bracket, your refund for the RRSP contribution will
be $3,150. This means you are out-of-pocket only $7,350.
If you are in a 40% tax bracket, your refund would be $4,200, and you
would be out of pocket only $6,300.