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07 May 2019



Dim Sum

Not the yummy kind this time... 

Did you know that the size of your box has weight? I don’t mean the number of ounces or pounds it might register on a scale. I mean to say that the volume of your package carries as much significance to FedEx (or any Overnight carrier) as its heft. 

It makes sense when you think about it. Not only does a plane carrying express deliveries have a limit to the amount of weight it can carry, but it also has a limit to the volume of packages it can fit in its belly. Therefore, when determining the cost to ship a package, FedEx will take into serious consideration the dimensions of the box as well as the number it hits on a scale. 

This is called Dimensional Weight, or DIM Weight for short. FedEx (and UPS) use a specific formula to determine the DIM Weight of every package. That number is compared to the box’s actual weight. Whichever value is higher determines the cost to book that shipment. 

In the reptile shipping community, our most common deliveries are small, young animals. Boxes tend to be relatively light-weight. This means that in most cases, the DIM Weight of the box will be higher than the actual weight. With aquatic shipping, the added weight of water used in shipping fish or corals can be enough to tip the scales toward actual weight being the deciding factor, but it’s still common for DIM Weight to be used. 

The formula for determining DIM Weight is (L x W x H) / 139. That's length times width times height divided by 139. The number 139 is called the DIM Factor. 

A 7x7x6 box has a DIM Weight of 2.12, which is rounded up to 3 pounds. 
A 15x11x7 box has a DIM Weight of 8.3, which is rounded up to 9 pounds. 

Put the same baby snake or gecko in each of those boxes and they may each weigh in at around 2 pounds, total. If they both weigh the same, shouldn't they cost the same to ship? No. The DIM Weight is larger in both cases, so that is what FedEx will use to charge. At 3 pounds, the 7x7x6 box might cost $65 to ship while the 9 pound 15x11x7 box might cost $95 to ship to the exact same address. That's a difference of $30!

A second example, using some of our new box sizes, shows just how much difference a couple of inches can make: 

An 8x8x7 box has a DIM Weight of 4 pounds. 
A 10x10x10 box has a DIM Weight of 8 pounds. 

That's twice the billable weight for only a small increase in size! To ship these two boxes from Texas (for instance) to California could cost $70 for the smaller box and $90 for the larger. Twenty dollars more for just a couple of inches on each side.

What does this mean for you? Primarily, it means the size of your box matters! A difference in dimensions of just a few inches can have a big impact on the cost of shipping. If you have a choice between two different box sizes, both of which would be appropriately safe to ship your animal, then go ahead and choose the smaller of those two boxes and save some money. 

Click here to find a full selection of box sizes, either in kit form (everything you need for a single shipment) or buying in bulk.

One key thing to keep in mind when considering box size: There IS such a thing as too small. 

Don’t cram a large snake (or lizard) into a tiny box. Yes, they are very bendy animals and most of them enjoy smooshing themselves into tight spaces, but that is NOT a safe way to ship them. Any animal being shipped needs enough free space around it to allow for cushioning to absorb the shocks and bumps that will be encountered during the shipping journey.

If a heat pack must be used in your shipment, there MUST be room in the box to allow for it. A tiny 7x7x6 box will concentrate that heat in a very small space and greatly increases the risk of overheating the animal inside. We recommend a 12x9x6 as the minimum size box when using a heat pack, and at that, there must be room in the box to allow adequate space and cushioning between the heat source and the animal. Never use more than one heat pack per box, unless shipping a very large box, such as 30x16x10, in which case you might tape one heat pack at each end of the long box. 

Another thing to bear in mind is that accuracy matters! Measure your boxes properly to get the best bang for your business buck. You might think you’re getting a deal if you casually estimate the box dimensions a little bit smaller than they actually are. You’ll pay less for that label, right? Wrong. When the box hits the FedEx conveyor belts, it is scanned by lasers to measure its exact dimensions. If you’ve underestimated the size of that package, FedEx will charge SYR for the difference in costs, and then we will have to charge you, and that’s no fun for anyone! 

If you’re a "better-safe-than-sorry" sort of person and estimate the size of your box too large, you’ll end up paying more than you need to. And will FedEx reimburse you for overpayment after they laserize your shipment? No, of course not. You’d just be out the money you didn’t need to spend. 

So, measure accurately. If your box is bulging a bit at the sides, be sure to include that extra width because FedEx surely will. And always round up to the next inch, because FedEx doesn’t like fractions. (Who does?) 

Appropriately sized boxes and accurate measurements in both dimensions and weight will give you the absolute best chance to get the best deal on every shipment you send! 


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