While potatoes vary greatly in size or shape, potatoes produced commercially are ordered and packed based on average size and weight. The range is from extra large, with the a
…verage potato weighing 560 gm (20oz) down to small, with the average potato weighing 185gm (6.5 oz). It could be said therefore that the "average potato" is about 375 gm (13.25 oz). The packaging of potatoes this way is reflected in the potato stalls and pre-packed bags found in supermarkets and fruit & vegetable stores. Most have scales handy - so you can weigh a few samples from different stalls and get a feel for what each size weighs. Very large potatoes are good for making long fries. Smaller potatoes are ideal for steaming or baking whole. For virtually everything else mid-sized potatoes are the best - as you can always cut them to size. (MORE) 
