This depends of course on how hungry you are and how many herrings you use per bread. A hungry enthusiast eats somewhere between 6-12 herrings. 1 herring means one whole surströmming, from each fish you get 2 fillets.
​
1-2 herrings per bread is what people generally eat, and 2-4 breads with surströmming is what most people have room for.
Some people skip the flat bread and just enjoy the fish along with varm potatoes, butter, tomato, chopped red onion and sour creme, and a cold beer.