For every 4 teeth, cog or chainring, you'll need to add one full chain link and vice versa.

Example: I changed from a 44/17 to 47/18, 4 teeth difference but the same ratio. The rear axle sits on the very same spot in the dropouts as my old 44/17.

Changing to a 46/16 will require you to remove one full link and it will be closer to the centre of the dropouts.