Master Carton
A master carton, also called a case pack, is the outer shipping carton that holds a fixed number of units or inner packs of a single SKU as packed by the supplier.
Why it matters for ecommerce brands
Master carton specs decide how efficiently inventory moves through freight, receiving, and storage. Consistent carton quantities and dimensions let a warehouse receive by carton instead of counting units, and they set how many units fit on a pallet or in a container. Retailers also order in case-pack multiples. For example, 24 units per carton and 40 cartons per pallet give 960 units per pallet. Switching to 20 units per carton with the same carton count drops that to 800 and raises freight cost per unit.
Formula and calculator
Units per pallet = units per master carton × cartons per pallet
Common questions
- What is the difference between a master carton and an inner pack?
- The master carton is the outer shipping case that moves through freight and warehouses. An inner pack is a smaller grouping of units inside it, such as 4 boxes of 6 units in a master carton of 24.
- How many units should go in a master carton?
- Pick a quantity that keeps the carton light enough to lift safely, often under 50 pounds, fits your pallet pattern, and matches how retailers or your 3PL order. Keep it the same on every shipment of that SKU.
- What information goes on a master carton label?
- At minimum the SKU, quantity, and carton number, usually with a barcode. Retailers and 3PLs may also require a GS1-128 label with an SSCC so the carton can be matched to the ASN.
Cite this entry
"Master Carton." Fulfillment Lexicon, last reviewed October 16, 2026. https://fulfillment.wiki/glossary/master-carton/