It would be completely safe to draw 15 amps from an outlet on a 20 amp circuit, thus having 5 left over for other stuff. There are outlets marked with a 20 amp rating just to be safe in the pass-through capacity.
No single appliance with a 5-15 plug is supposed to draw more than 15 amps. If you have one that does, it's an issue of having the wrong plug, not the wrong outlet.
No single appliance with a 5-15 plug is supposed to draw more than 15 amps. If you have one that does, it's an issue of having the wrong plug, not the wrong outlet.