If you’re an Amazon Prime member I bet this has happened to you. You order something small or a combination of small things. The box that you receive is gigantic with a bunch of unnecessary packing material. This happens relatively frequently to me. The protein bars in that picture above I order somewhat regularly. Each and every time the box is a wildly different size, ranging from almost perfect to way off like that one.
The more I thought about this, the less it made sense. We put a ton of effort into optimizing everything shipping related, and one of those things that has become increasingly important to account for is dimensional weights, or DIM weights.
DIM weights are the shipping carriers’ solution to large, light packages that would cost very little to ship if they were rated solely on their weight, but should cost more in theory because they take up a lot of space. For any package shipped with UPS or FedEx, and for some shipped with USPS, you calculate the package volume (length x width x height) and then divide it by a dimensional divisor provided by the shipper (often 166 or 139). If the resulting number is greater than the weight of the package, you’re billed at that weight instead of the actual weight.
An example would be a 2 lb shipment in a 12″ x 12″ x 12″ box. With a dimensional divisor of 139, the DIM weight is 12.43 lbs and you would in turn be billed the 13 lb rate if you shipped that package instead of the 2 lb rate. Here are the reference pages with more information from UPS, FedEx, and the USPS.
This obviously ups the stakes for picking proper box sizes – no need to pay a higher rate for dead space – and makes Amazon’s apparent apathy for box size all that more perplexing. We stock over 40 different boxes, ranging from 6″ x 3″ x 3″ to 24″ x 24″ x 24″ in size. I’ll often get packages from Amazon and think “we have a better box for this”, which doesn’t make any sense given our minute scale relative to Amazon.
Either they don’t care about these costs (unlikely) or there is some non-obvious reason why they don’t care much about box size. My first inclination was to think that maybe Amazon has negotiated DIM weights out of their rates, that they simply pay by weight. But Fulfillment by Amazon very clearly charges it’s customers DIM weights so that doesn’t seem like the answer (unless they’re skimming the DIM weight profits off the top), plus it’s hard to believe that the shipping companies would cave on this despite Amazon’s bargaining power.
My best guess is that there is some sort of operational trade off that they make. What seems like sloppiness is actually well calculated. This is more like the Amazon way. We know that they use chaotic storage. In looking at this picture from a tour of their warehouse, it looks like the packer only has a dozen or so box options. My guess is that it’s cheaper to ship the item out from the closest packing station, which probably is right near a truck loading station, then it is to move it throughout the warehouse to a location where there is a better fitting box.
Then again, that seems like a solvable problem too. Or, maybe they just don’t carry that many box sizes…but why? Boxes are cheap and don’t take up that much space relative to the cost savings of lower shipping rates, less packing material, and less damages (at least, we have less damages with better-fitting boxes).
I’m genuinely curious about this! If you have any insight, especially if you use FBA, please let me know in the comments.
Update 12/28/18: – I published a follow-up post Is This the Reason Amazon Sends Small Items in Large Boxes?