A UK-based shop I look after ships products worldwide. For anything under 2kg they use Royal Mail which have prices by weight across 4 shipping zones, so I have just used a simple lookup table.
For anything over 2kg, the shop would send via courier, and although couriers charge by weight, the final cost could be vastly different depending on which country they are shipping to.
It seems that couriers do not price by shipping zone, but instead price by weight and the specific country. What is the best way of getting the shipping price accurate?
Is there such a thing as an extension which will take the weight and shipping address, send the details to a shipping company, and return a shipping cost to charge to the customer?
If this is not possible, how are other people tackling this issue so that they do not under-charge for international shipping?