Plus Size Knitwear Sourcing: Cost, Fit and MOQ Truths

Short answer: extended sizes need their own pattern block from about 1XL/2XL upward, cost 12-25% more in fabric, and must be fitted on a live plus-size model — not graded from a size M. Budget roughly 1.35× the fabric of a size M at 2XL and about 1.7× at 4XL, plan a separate block for every two to three sizes above the base, and buy a size ratio that reflects real demand rather than a symmetrical curve. Brands that grade 3XL up from a medium block routinely see return rates above 25% on those sizes.

Plus-size is the largest under-served category in knit apparel and the one most often launched badly. The failure is almost always the same: a brand develops a sweater on a size M fit model, grades the pattern up four sizes with the standard rules, and ships a garment that pulls across the bust, rides up at the front and has sleeves two centimetres short. Then it blames the factory.

Why Grading Stops Working

Grading applies fixed increments — chest, length, sleeve — across a size set. It works over a small range because bodies scale roughly evenly. It breaks above about two sizes from the base:

The practical fix is a break point: one block for the core range (XS-XL), a second for 1XL-3XL, and a third above that if you go to 5XL. Two blocks cost more in development and save the category.

What It Costs

Getting the Size Ratio Right

The most common commercial mistake is buying a symmetrical curve.

Fabric Choices That Help

Fit Testing: Non-Negotiable

Conclusion

Extended sizes are a development project, not a grading exercise. Two blocks, honest fabric allowances, a size ratio based on actual demand, and fit testing on the bodies you are selling to. Do that and the category becomes one of the most loyal in your catalogue. Skip it and it becomes a returns problem you quietly discontinue.

Key Takeaways for Buyers

How We Develop Extended Sizes

HONGTEX develops separate blocks for extended sizes rather than grading past the base range, and we fit on live models in the target size before bulk — including washed fit, which is where most knit sizing surprises show up. If you are adding extended sizes to an existing style, send the current block and we will tell you where the break point should sit.