Master Cartons vs. Inner Cartons: What Do I Need to Tell My Manufacturer?

Master Cartons

Just last week I was asked by a customer of ours for some guidance on developing master cartons and inner cartons.  The question started out like this:

“We were thinking to set our master carton size to 6 units – does this work with Shipcalm? Then we can also do a case of 8 cartons, to make 48 units. 
Not sure if this terminology is exactly correct. Maybe we can have a quick chat to confirm?”

In an effort to answer his questions let’s start with the two key terms everyone should know so that we can talk about what he was really looking for.

Master Carton

This is referring to the outer box that contains your goods at it’s the largest quantity other than a pallet.  Essentially from the manufacturer, you could expect to receive nothing but Master Cases either floor loaded in a container or on pallets.

Inner Carton

If the master case is broken up into smaller groupings of the product that would be done using an inner case.  We’ll go into more detail below on why you might want to do that.

inner carton and master carton setup
Example of a Inner case and master case setup.

Headings are separate blocks as well, which helps with the outline and organization of your content.

It’s important to note that both of these terms are used to describe the organizational containers that hold a single SKU.  Essentially you manufacture a SKU and put it into inner cases & master cases which is typically how that SKU will be stored in a warehouse prior to a retailer or end customer ordering it.

With these two concepts in mind, the configuration he was looking for was 6 products in the inner case, and 8 inner cases in the master case making it a master case of 48 total units.

While there are no issues doing a configuration like this there are other factors that you can take into your decision-making process.  That said it would be good to know what the weights and dims of the inner case and master case would be.  For example, if 5 units in the inner carton instead of 6 make it under 1lb, that is a major advantage on the shipping side of things.

Carton Sizing

For inner cartons, you can think in term of shipping weight and sellable at wholesale quantities so that you can send retailers 1 full inner case.  If your wholesalers want 4 at a time, do 4.  If you can sell them on 6 at a time, do 6.  This allows you to do wholesale orders that don’t require repacking of the product. 

For master case, you just want a reasonable case size that is planned around fitting on a pallet. The standard North American pallet is 40″ x 48″.  For example, if you master cases are 20″x24″, then each row is a perfect fit of 4 where you can label the outside of each case and position to be seen on the outside of a pallet without trapping an invisible case somewhere inside the middle.  This typically means designing in case quantities of per pallet row of 4, 6 or 8.

20×24 = perfect row of 4

20×16 = perfect row of 6

20×12 = perfect row of 8 

If you did a row of 9 (3×3) or 12 (3×4) that would be bad because you end up with cases in the middle where once fully stacked you can’t see the outside of that master case.  That said if the configuration is 12 (2×6) using a box that is 20×8 no issue at all! 

In addition to considering how a Master Case fits on a pallet, you can also consider the shipping costs on a per lb or per product basis for a Master Case.  There tends to be a sweet spot at 50lbs per box max with regards to optimizing your per pound freight cost from someone like FedEx or UPS.  This means that a single master case that holds 50 Products at 50lbs is better than 2 master cases that hold 25 products at 25lbs.  However a case over 50lbs is not only hard to physically maneuver around, but it also provides an increase in the price per pound.

While this can all feel very complicated, it certainly doesn’t need to be.  Contact ShipCalm and we can work with you to optimize your inner cases & master cases to streamline operations.  We’ll help to provide recommendations based on the specific ways you like to run your business while continuing to optimize for freight carriers and storage.