I remember reading from someone (might of been Karl but it was a while ago) that engine capacity doesnt affect overall BHP for a turbo motor, can someone explain how this works?

I know it effects other things like torque, power delivery, drivability but I'm just on about BHP.

Is it something to do with the compressed charge air effectively replacing the lost capacity of a bigger N/A engine?

Go easy on the techy terminology, I'm ok with theories and why things work but not to hot on some of the terms.