pot-sized raise = $ in the pot + $ for you to call

In this case, that = $6.50 ($5+blinds) + $4.50 ($5 - your SB) = $11

Since $5 has been bet, you would make it $16. When I'm oop I usually bump it up a little b/c I don't mind taking it down pre-flop, so I'd make it $20.