How do I determine how many packages are needed for my customer’s order/cart and their dimensions?

It is difficult to calculate number of boxes and dimensions when you don’t know what shipping box will ultimately be used. Unfortunately all shipping carriers are transitioning into using dimensional weight for rating.

The bad news: Trying to figure out which products can fit in what box and the most optimal way is currently NP-Hard which means it is virtually impossible to solve (and currently hasn’t been). If you don’t have a specific set of shipping boxes, figuring out the dimensions of the unknown is simply impossible.

The good news: In ecommerce you can usually approximate pretty well.

Here are a few ways:

  • Limit the different shipping boxes you use and provide those dimensions during rating that you know will work with the combination of products in the cart
  • Average out your box sizes using a weighted average of frequency of box use. What is the average size box that you use?
  • Rate as if you are going to ship everything in a separate box and assign each product to a box (always in shipper’s favor)
  • Take each product in cart and take the maximum dimensions of each one and use that (will not always be in shipper’s favor)
  • Track and average out actual current and past shipping costs per product and use that instead
  • Also just custom rules of thumb can help if the SKU list is small. For example we worked with a wine company that never shipped more than 12 bottles in a single box.