Whether you sell to brick-and-mortar stores or make your living through e-commerce, knowing different pack sizes can be helpful in more than one way.
This guide will explain key pack size terminology and help you determine which configurations best serve your supply chain. From case packs to warehouse packs, each type plays a role in how your product moves through the system and into stores.
What Are the Different Pack Sizes?
Pack type refers to how many selling units (or “eaches”) are grouped together in different layers of packaging. Each layer plays a distinct role in moving products from supplier to shelf.
Here are some common industry terms related to pack sizes:
Each (Selling Unit): The each, or selling unit, is the smallest sellable unit and is often what a customer purchases directly.
Inner Pack: An inner pack is a bundle of multiple eaches grouped together within a larger carton. These groupings help retailers manage inventory for smaller orders without having to break down an entire case.
Master Pack (Case Pack / Vendor Pack): The master pack, also known as the case pack or vendor pack, is the larger carton that contains either multiple inner packs or multiple eaches.
Warehouse Pack (Break Pack): A warehouse pack, sometimes referred to as a break pack, is a smaller subdivision inside a master pack that is designed for redistribution.
Master packs and inner packs serve different roles in product packaging and distribution, and knowing the distinction between them helps prevent confusion during shipping, receiving, and setup.
Master Pack (Case Pack / Vendor Pack)
The Master Pack refers to the outer box. It provides product protection, consolidates multiple selling units into a manageable carton, and reduces the number of boxes handled at every stop along the way. Retailers usually receive master packs stacked neatly on pallets or floor-loaded into shipping containers.
Related Reading: What is TI/HI?
Inner Pack / Warehouse Pack
On the other hand, the Inner Pack is the smaller grouping of products that usually arrive inside the Master Pa
ck. All items inside an inner pack are the same product (one SKU). If multiple product types are
grouped together, it’s no longer an inner pack—it’s a kit.
Inner packs are often used to protect fragile or heavy products, and they make it easier for warehouses to handle and distribute smaller quantities without breaking down an entire case.
Related Reading: What is Aggregate Inventory Management?
Examples of the Different Pack Sizes
Example 1: Vendor Pack 48
In this setup, the supplier ships one master case of 48 units to the distribution center. The DC doesn’t split it apart; the entire case is sent directly to stores.
This approach is efficient when stores sell large quantities of the product each week. Fast-moving items like bottled water or household staples benefit from this configuration because the volume justifies sending full cases.
From the supplier’s perspective, this method is very cost-effective. It requires fewer packaging materials, less corrugation, and simpler handling. Fewer boxes mean fewer touchpoints and reduced labor at every step.
For retailers, however, this configuration can be restrictive. Stores must order in full-case increments of 48 units, whether they need that much or not. A location selling only 10–15 units per week may sit on excess inventory, while the replenishment system won’t trigger an order until it reaches the threshold for another 48. This can create a mismatch between actual sales and shipments, sometimes leading to overstocks or even temporary gaps on the shelf.
Example 2: Vendor Pack 48 / Warehouse Pack 12
Here, the supplier still ships a case of 48 units, but the case is designed to split neatly into four warehouse packs of 12 units each. At the DC, those smaller packs can be redistributed to stores based on weekly demand.
This strikes a balance between supplier efficiency and retailer flexibility. The supplier does incur higher costs—more corrugation, printing, and handling are required to create those subdivisions. But the payoff is flexibility for stores. A location selling 10–15 units a week can replenish with just 12, keeping shelves stocked without flooding the backroom with extra cases.
In practice, this configuration is often used for moderately selling products where case packs would be too much, but breaking down to single units would be overkill. It gives retailers replenishment options without requiring suppliers to absorb the high costs of handling each individual unit.
Related Reading: What is Vendor Managed Inventory?
Example 3: Vendor Pack 48 / Warehouse Pack 1 (Eaches)
In this example, the supplier still ships a case of 48, but every unit is treated as its own warehouse pack. The distribution center can break the case down completely and ship exactly the number of units a store needs.
From the retailer’s perspective, this is the gold standard for flexibility. Stores avoid overstocking, and replenishment can match sales almost perfectly. If a store only sells three units a week, the system can order just three.
For suppliers, however, this is the least cost-effective method. Breaking down to eaches increases packaging requirements, labeling, and DC labor. It’s a configuration best reserved for high-value or slow-turning products where minimizing overstocks is more important than maximizing packaging efficiency.
How Do Warehouses Choose Their Pack Sizes?
Pack size decisions are driven by a mix of efficiency, retailer needs, and shipping practicality. Warehouses aim to select carton sizes that reduce handling, maximize space, and align with how products are sold.
Carton Sizing
Suppliers must consider the inner cases in terms of the shipping weight and selling them at wholesale or bulk quantities. This allows them to send a retailer one fully-packed inner case.
If the retailer requests four inner cases, then the supplier should ship one master case with four inner cases inside. If the supplier can get them to go up to six, it will be even better. This way, suppliers can fulfill wholesale or bulk orders that do not require product repacking.
For a master case, it’s essential that suppliers select a reasonably sized case that they can safely stack on a pallet. The standard size of a pallet in North America is 40 inches by 48 inches.
Therefore, to choose the master case sizes, suppliers must plan to make them fit in the pallet. If a supplier has 20-inch by 24-inch master cases, for example, and every row has four cases, this assists the labeling process. The supplier would be able to label each case on the outside and position them so that they are visible when standing next to the pallet.
How Do You Calculate Pack Sizes?
What does this mean regarding the calculation of pack sizes? In the examples provided above, it means that suppliers design their supply structure in quantities of four, six, or eight per pallet row.
Review these measurements and the outcome of how they’d fit onto the pallet.
20 inches by 24 inches = row of 4
20 inches by 16 inches = row of 6
20 inches by 12 inches = row of 8
If a supplier tried to do a row of 9 or 12, it wouldn’t work well because there inevitably would be cases in the middle. Once the supplier has stacked the pallet, the outside of those master cases wouldn’t be visible.
On the other hand, if the supplier configured its cases in such a way that it was 12 (2 by 6) and used boxes that were 20 inches by 8 inches, it would have no problems. It’s all about configuring the master cases to sit atop the pallet.
Note: Suppliers should also consider the cost of shipping per product or pound for a master case. The general rule of thumb is 50 pounds per box at the most when trying to optimize the freight costs per pound with a carrier like UPS or FedEx.
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