is food more expensive in koh samui then in pattaya, because it is an island?

Yes.

how much more?

5 hours ago, parafareno said:

how much more?

No idea.

How much does food cost in Pattaya?

I pay 60 baht for pad krapow moo with an egg and rice.

Depends where you shop, and what you tend to eat. Tops? or Talad?  Flash restaurant? Or local Thai food shack?

 

But in general Samui is expensive because it is an island. Therefore greater shipping costs. Fuel and ferries.

 

19 hours ago, parafareno said:

how much more?

millions. stay in pattaya IMO

I found it opposite last I visited Pattaya – food seems to be very expensive there due to being a major tourists destination – however, it's a question of what you seek of food and knowing the goo more local restaurants. Instead of the low season bargain at W with a candlelight dinner for two offered for only 15,999 baht – I shall add, for the matter of good sake, that it included a bottle of the house red wine, but service charge and tax came on top – you can find good meals in street kitchens from around 50-60 baht including free drinking water, and local restaurants for about 80-120 baht for a delicious Thai-dish, farang food often from 150-200 baht and up. Pretty much up to you...