Size Run Versus Pre-Pack: Which Should Your Warehouse Use?

A set of apparel units across a range of sizes for a specific style and color.

Size Run

A set of apparel units across a range of sizes for a specific style and color. The term overlaps with "pre-pack" in many organizations, but there are operational distinctions warehouses and 3PLs should understand when choosing fulfillment and packing strategies.

Both size runs and pre-packs are grouping strategies that simplify receiving, allocation, and shelf-ready presentation. Choosing between them (or deciding how to apply both) depends on channel requirements, SKU velocity, merchandising needs, and packing efficiency goals.

Key Differences

Although used interchangeably, warehouses treat the two concepts differently in practice:

• Size Run: Focuses on the ratio of sizes for a single style-color SKU. A size run prescribes how many of each size ship in a pack or carton.
• Pre-Pack: Refers to retail-ready cartons or bundles created for store shelving that may contain one style in multiple sizes, or multiple SKUs grouped by color or promotion. Pre-packs often include barcode labels for direct store receiving and merchandising.

In short: every pre-pack can follow a size run, but not every size run is delivered as a store-ready pre-pack. The difference matters for labeling, carton configuration, and whether a store receives floor-ready cartons or a bulk assortment to be reboxed.

When To Use Size Runs

Size runs are best when the primary goal is aligning production and replenishment with size demand.

• High-volume basics: Use runs to order predictable ratios of sizes for staples like T-shirts and leggings.
• Centralized allocation: When distribution centers allocate to many stores, consistent runs simplify automated allocations.
• E-commerce with standardized picking: Runs reduce SKUs per carton and make pick rules easier in a WMS.

When To Use Pre-Packs

Pre-packs work best when stores want minimal handling upon receipt or when merchandising must look uniform across locations.

• Store-ready assortments: Retailers that expect shelf-ready shipments prefer pre-packs with hang-tags and display-ready labels.
• Promotional packs: Bundles for promotions or seasonal floor sets need pre-packs to ensure consistent presentation.
• Small-format stores: Direct-to-store pre-packs reduce labor and space needed to re-sort assortments.

Operational Impacts On Warehouses

Deciding between runs and pre-packs changes receiving, packing, and labeling processes. Pre-packs increase packaging steps but reduce downstream store labor. Size runs prioritize production ratios and can be unpacked and reallocated at the DC level. Key operational impacts include:

• Receiving speed: Pre-packs speed up store-facing shipments; size runs speed up inventory counting and replenish decisions.
• Carton handling: Pre-packs need clear retail labels and sometimes hangers or folding boards; size runs may arrive in inner packs needing sorting.
• WMS rules: Configure carton contents and pick-to-carton logic depending on whether you handle pre-packs or break runs for mixed picking.

Cost And Inventory Considerations

Pre-packs reduce store labor but increase packaging cost and may increase shipping volume. Size runs reduce production complexity and enable smaller pack sizes, which can lower shipping costs but shift labor to the DC for splitting and allocation. Consider these trade-offs:

• Packaging cost: Pre-packs use more materials and sometimes specialized labels or hangers.
• Shipping density: Pre-packs may be less dense if retail-ready fixtures are included.
• Inventory accuracy: Size runs improve traceability of size ratios; pre-packs can mask individual size counts unless clearly labeled.

Choosing The Right Approach

Selection depends on channel mix and cost allocation. If most sales occur in-store and labor at stores is expensive or limited, pre-packs are often preferred. If you operate a large DC supporting omnichannel fulfillment, standardized size runs with flexible allocation rules may be more efficient. Hybrid models are common: use pre-packs for high-traffic stores and size runs for e-commerce or lower-volume locations.

Practical Example

A brand selling a performance tee may ship high-volume stores with pre-packs of 12 units (1 S, 3 M, 5 L, 3 XL) that go directly to floor. The DC retains the ability to break bulk size runs for online orders and small boutiques where a different size mix is needed.

In short, the Size Run and the related concept of pre-packs are complementary tools. Use size runs to codify size ratios and production planning; use pre-packs when store-ready presentation and reduced store labor outweigh additional packaging and shipping costs.