Is This the Reason Amazon Sends Small Items in Large Boxes?

One of the great mysteries in shipping is why Amazon, with all of their logistics expertise, often sends small items in big boxes. I wrote a post about this a few years ago. The comments section is particularly enlightening. We have lots of theories, but no answers. This practice is particularly unfair to FBA shippers who have claimed that they end up paying higher rates because Amazon charges them DIM weights on those unnecessarily big boxes.

Yesterday I was listening to This Week in Tech and the topic came up. Leo Laporte, a person I would consider very well connected, had this to say (minute 47 if you’d like to watch/listen to the full conversation):

I’ve been told there’s a reason. It’s for packing the truck. Amazon is so smart in their algorithms that they choose the boxes not merely for the thing that’s in it, but also so how they will all fit into the truck so that they don’t slide around in the truck.

This does make some sense. The very first comment on that last post from Peter suggested as much:

I do think that amazon has that much bargaining power and is either getting full truck rates + some local delivery or they do skip dim overall. I am sure they profit off dims they charge FBA customers.

It does seem quite unfair to be charging FBA customers DIM weights when Amazon is picking that larger box size to pack their truck better. If this is ever proven to be true, I’d imagine FBA sellers will be up in arms (but, even if they are, do they have an alternative? Amazon is scary…)

Then again, all of this goes against what Bruce said in the comments section, and he seemed to have inside knowledge because his “son-in-law oversees facilities maintenance services for Amazon’s fulfillment centers in the southwest”. His theory was that it was simply Amazon being efficient (avoiding repacking, less training, etc).

Someday we’ll know for sure…maybe.

6 comments on Is This the Reason Amazon Sends Small Items in Large Boxes?

  1. Rob says:

    By “FBA Customers” do you mean the sellers? I’m pretty sure sellers using FBA are charged based on cubiscans of their actual items plus the weight of a box to put them in. The fees I’ve been charged in the past certainly bare this out. After all, it’s not for us to know if our items will ship out to the end customer with items from other sellers in the same box.

    I think the most likely answer is that’s they get good rates, packers have an incredibly short time to pack items and so they don’t have access to a huge selection of box sizes – perhaps different packers have access to different box sizes, but during peak the system is over ridden and orders that would ordinarily ship in a smaller box are sent to a packer that only has access to larger boxes.

    • Adam McFarland says:


      Yes, I did mean FBA sellers, I should have phrased that better.

      That’s an interesting point. It makes total sense. When I review Amazon’s help page about how they charge sellers it says that they charge:

      The greater of the unit weight or dimensional weight + packaging weight.


      Unit weights, dimensions, and other measures used to calculate fees are as determined by Amazon and are subject to variations based on packaging. Dimensions may change based on packaging type.

      Which makes me think that if a rushed Amazon employee grabs a bigger box than needed, you as the seller might get penalized by being charged the higher rate? I hadn’t considered the situation where products are mixing from other sellers though…

      • Rob says:

        The fees are set based on the cubiscan done the first time an item leaves the warehouse (or subsequent rescan).

        For a given item, at a given price the only time I see the fulfilment fees varying is when there’s a new fee schedule published. They certainly don’t vary from one order to the next ordinarily, which would be the case if it mattered what size box the amazon packer used or whether my items share a box with other items in an order. There are a lot of conspiracies at amazon but I honestly don’t think this is one of them.

        BTW, think there’s something up with the https on this blog. Either not applying at all or not redirecting non-https.

        • Adam McFarland says:

          Good to know, appreciate the insight. That certainly makes the most sense.

          I actually haven’t upgraded the blog yet to https. It’s on my long-term to-do list, not a super big priority at the moment.

  2. natevw says:

    Does dimensional weight perhaps not apply for certain nice-size packages? (Somewhat like the USPS “flat rate” boxes, only still based on actual scale weight?)

    I see on

    > We use unit weight (the item’s actual weight) for all standard-size packages that weigh less than 1 lb, as well as for all special oversize packages.

    And even FedEx has one slight nod to this on

    > FedEx Express packaging offers you a practical and advantageous solution. Dimensional weight standards are not applied to this packaging, providing that the dimensions have not been changed.

    …though I couldn’t find any more details or mention of this on other dimensional weight pages. So maybe I am misunderstanding and/or reading too much into things.

    • Adam McFarland says:

      That’s a good point Nate. For light items and/or items going out via certain shipping services, DIM weights might not apply.

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