Math is Our Friend: A Guide to Cargo Calculations for Logistics Professionals

Math is our Friend
Corey Wagner, our Director of Regional Commercial Development, ponders about how much you can really fit into a container.

While she would likely poison my dinner or make a chubby “Rob Doll” for her voodoo pins if she knew I was writing this in a public forum, my wife is lousy at math. I mean lousy. This woman is a great teacher for our children; she is impossible to beat at Scrabble or Trivial Pursuit; she is at least three times smarter than I am… and, she has a panic attack if you mention “square root” or “divisible” or (God forbid) “numerator.” I tattle on her because I want all of you who suffer from Mathoplexy to know that you are not alone, and some very bright people out there are as terrified of mathematics as you are. For me, black mamba snakes defy all rational explanation and the smallest thought of one causes me to tremble and get under my desk. I digress.

If you want to excel in our industry, you must face your math phobia head-on. From perfect Customs entries, to accurate pricing/invoicing, to clean logical logistics, you better have a competence for numbers and calculations. So, job one is to summon the courage to ask for help. As adults, we are taught to feel foolish for not knowing everything under the sun. This is particularly true for language skills and mathematics. After all, we spent close to 20 years trundling off to school to learn this stuff. But, if you are not reasonably well prepared and confident with numbers, you will create a self-imposed ceiling for yourself. Don’t do that!

The Basics

For those of you in between a panic attack and full “numerical” self- confidence, let’s summarize the fundamental math of our business:

  • To get kilos from pounds, DIVIDE by 2.2046
  • To get pounds from kilos, MULTIPLY by 2.2046

Ta da! That was easy as pie… now MEMORIZE it, already. This is a key building block.

Volume (Ocean Freight):

You usually get dimensions in inches. So, the typical scenario presents you with these calculations:

  • Length (inches) X Height (inches) X Width (inches) X Number of Pieces = Volume Basis
  • Volume Basis DIVIDED by 1728 = Cubic Feet
  • Cubic Feet DIVIDED by 35.314 = Cubic Meters

If you have centimeters, you DIVIDE by 2.54 to get inches.

If you have millimeters (rare), you DIVIDE by 22.54 to get inches.

Volume (Air Freight):
  • Length (inches) X Height (inches) X Width (inches) X Number of Pieces = Volume Basis
  • Volume Basis DIVIDED by 366 = Volume Kilograms
  • Volume Basis DIVIDED by 166 = Volume Pounds

Note 1:  It is essential with air calculations to understand that some carriers (primarily cartage companies for domestic pick-ups and deliveries) use their own chargeable basis. For example, one might charge based on a “volume pound factor of 250.” This means your cost and invoicing calculations would use 250 in place of the 166 above.

Note 2:  There is a very handy cheat sheet on our Resources page on container specs.

Abstract Math for Advanced Student

To me, the absolute key to good cargo math is the power of your imagination; that’s why I’m calling this “abstract” math.  You need to be able to imagine cargo from a size and shape perspective and then imagine that cargo in its potential shipping conveyance (loose, containerized, consolidated, etc). When you can imagine these things, you can sketch the configurations necessary for making solid logistical choices and comparisons.

Example: Over-length Surcharge for LCL Ocean Cargo

Have you ever wondered why you may have gotten hit with an extra charge for having a LONG shipment?

The answer comes from our old friend, Mathematics. When you consider two simple facts, you begin to see the answer:

A 40’ standard container has usable dimensions of 39’5” (Length) X 7’8” (Width) X 7’10” (Height).  A typical shipping pallet is just under four feet square (42-46 inches in length and width, often height too).

So, if you get the pallets very, very cozy with one another (after a few adult supervised dates, of course), you can expect to have 10 rows of 2 pallets (with the potential to double stack sturdy cargo). So, when you show up with your stuffed black mamba snake for shipment (far, far away from this author, please) at ten feet long and two feet wide, you are limiting the ability to fill the container efficiently. It takes THREE pallet positions to accommodate said dreadful mamba.


Get comfortable (raise your hand if you need help!)

Get confident (help your company plan well!)

Get creative (analyze, analyze, analyze!)

-- Robert Burdette
Vice President, Strategic Development


  • Stephan Bucher

    @Robert: I just was wondering if you can help me with my dilemma and calculate how many seconds have past since I had my morning coffee at 07.45 hrs 2 years ago on March 3rd … Joke aside; indeed it is relevant for everybody to have these basic formulas memorized to understand moving freight from A to B.