How many hand bags can a passenger carry in an international flight?

Usually one can carry two hand bags in an international flight, but one might be allowed 3 handbags in few flights if it is small, but one thing one needs to remember if a hand bag is remarkably big one may not be able to fit it in the luggage space above the seat or  the officer of the airlines might ask you to book as a paid luggage if you have already book two big luggage and it is expensive.