How to Source Inclusive Size Ranges (XXS–6XL): A 2026 Guide for Brands

If you’re building an apparel brand in 2026, offering only “standard sizes” is no longer enough. Customers want clothing that fits their bodies—whether that’s XXS, 6XL, petite, tall or something in between.

But here’s the problem most brands face: Sourcing inclusive sizing is harder than it looks.

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actories may tell you they can “do all sizes.” But delivering a consistent fit across a wide size range? That requires experience, technical skill and the right approach from the brand.

This guide explains everything from adjusting pattern blocks to negotiating MOQs, so you can offer inclusive sizes without blowing your budget or sacrificing fit.

Why inclusive sizing isn't optional anymore

A few years ago, inclusive sizing was just a “nice to have.” Now, it’s a key revenue driver.

Market Growth: The global plus-size clothing market is expected to reach over $300 billion and is growing nearly twice as fast as the standard market. This gives brands a big chance to gain market share early.
The Real "Average": Studies show the average American woman wears a size 16 to 18 but many brands still stop at size 12. This means most people can’t find high-quality options.
Retention & Loyalty: Data shows that customers who need inclusive sizes are very loyal. When they find a brand that fits well, their Lifetime Value (LTV) often surpasses that of standard-size shoppers because they stop searching for other options.

The challenges of sourcing inclusive sizes

Expanding your size range is not as easy as just adding a few centimetres to your Tech Pack. It’s like zooming in on a photocopy—if you enlarge an image by 200%, it gets distorted and blurry. In the same way, simply making a size Small pattern bigger results in a poor fit for a size 4XL.
Here are the three specific technical hurdles brands face:

Standard grading doesn't work for plus sizes

Many factories use “straight grading,” which means adding the same increment (e.g., 2 inches) from one size to the next. This works fine for sizes XS to L. But above XL, it breaks down completely.

Bodies don’t grow in straight lines. If you use standard grading for a 4XL garment, you’ll notice:

Armholes that are too tight or dig into the skin.
Shoulders that droop or slip off.
Busts that pinch or flatten.

The "sample room" trap

Lots of manufacturers say they can make extended sizes to win your contract. They might even produce a perfect "Gold Seal" sample in a size 4XL.

The Risk: Their bulk production lines may lack the machinery or training to replicate that quality at scale. A factory might technically produce a 5XL. But if they are simply scaling up a size 8 pattern without changing the base block, the bulk order will be unwearable. This is why many growing brands eventually move away from platforms like Alibaba to specialised sourcing agents who can verify capabilities on-site.

Fabric behaviour changes across sizes

What works beautifully on a small frame can behave very differently on a larger one. For example, knit fabrics stretch more under weight and seams experience higher tension.

The Fix: Fabric choice is critical.

Higher GSM (Weight): Prevents fabric from becoming sheer or “grinning” when stretched over curves.
High-Recovery Elastane: Ensures waistbands snap back into place rather than rolling down during movement.

How to build truly inclusive size ranges

Start with accurate measurement data

Don’t use another brand’s size chart. Create your own chart using body measurement databases or 3D body scans. Your size chart is the base of your Tech Pack. If the numbers are off, the factory can’t fix it later.

Create separate blocks for standard and plus sizes

This is the most important step. A size block is the main pattern used to create all other sizes. For inclusive collections, you usually need two separate blocks:

Standard Block: XS–XL
Plus Block: 1XL–6XL

Why? Body shape, centre of gravity and posture differ across size groups. One block can’t fit everyone well.

Adjust grading rules

For plus sizes, grading increments should not be the same across all areas. You need bigger increases in the bust and hips but smaller ones in the shoulders and neck.

Fit test on real bodies

Fit testing is where inclusive sizing really matters. Don’t rely on mannequins. Always ask for a full "size set"—samples in every size or at least every other size like 1XL, 3XL and 5XL—before you approve bulk production.

Work only with factories that have experience

When vetting factories, ask these questions to reveal true expertise:

“Do you have existing blocks/patterns for sizes 2XL–6XL?”
“Do you use separate blocks for plus sizes?”
“How do you adjust grading rules above XL?”

At The Sourcing Co, we do more than ask these questions. We perform comprehensive factory audits to inspect patterns and cutting tables physically, ensuring the factory isn't cutting corners on the larger sizes.

Quality Control: The Inclusive Checklist

Quality control is even more important for extended sizes because seam tension and fabric stretch are more sensitive.

What to Inspect:

Seam strength: Pull tests are critical to ensure seams don't burst under tension.
Waistband rolling: Does the elastic collapse when the wearer sits?
Neckline stretching: Does the neck recover its shape after being pulled over the head?
Transparency: Does the fabric become see-through when stretched across the hips?
Print distortion: Does the pattern look warped on larger sizes?

If you skip quality control, you risk high returns, bad reviews and a damaged reputation before you even get started.

The Economics, Cost & MOQs

Does inclusive sizing cost more? Yes—but not dramatically.

Costs generally increase due to:

Additional patterns: You’re paying for a second set of blocks and grading.
More sampling: Testing a wider size range requires more sample rounds.
Extra fabric: Larger sizes consume more yardage (yield).
Higher packaging weights: Larger items weigh more, which can impact your logistics and freight planning.

The Sourcing Co Advantage: We help lower these costs by negotiating split-size MOQs. This means you can order sizes 4XL–6XL in smaller amounts without big surcharges. By grouping sizes or timing production with seasonal demand, we help you enter the inclusive market with less risk.

Success Stories: Brands Doing it Right

Need inspiration? Here are some brands that have set the standard for inclusive sizing:

Universal Standard: Renowned for having one of the best fit systems in the industry (sizes 00–40).
Skims: Excellent use of technical fabrics that stretch without losing opacity.
Aerie: Proved that showing real bodies in marketing drives massive loyalty.
Old Navy (BodEquality): Successfully implemented consistent pricing across all sizes (XS–4XL).

The Sourcing Co can help with inclusive size ranges

Offering inclusive size ranges isn’t just a trend; it’s the future of apparel. But it takes careful planning, technical know-how and the right factory partners.

When brands design for real bodies instead of idealised ones, they do more than boost sales—they build trust.

Explore our capabilities:

If you need help:

Building technical size charts and blocks.
Creating Tech Packs with correct inclusive grading.
Finding factories with proven inclusive sizing experience.
Managing sampling and fit testing.

Contact The Sourcing Co today to support your production from start to finish.