How to Plan a Size Run: Size Curves, Real Data and Reorders

Size run and size curve: the two numbers you are choosing

A size run is the list of quantities by size for one style in one color: so many Small, so many Medium, and so on. A size curve is the shape behind it, the proportion each size gets. Keep the two separate in your head. The curve is a judgment about who buys; the total is a judgment about how much cash and shelf space you can commit. Get the curve right and you can scale the total up or down without creating dead stock in the tails.

Write curves as units per batch rather than as abstract shares, because that is how you will order. "Out of every 50 units: 4 S, 16 M, 18 L, 9 XL, 3 2XL" is easy to multiply. The numbers in this guide are made up to show the method; they are examples, not data about any audience.

Where your curve comes from

Use the best source you have, in this order:

1. Your own past sales by size, corrected for sizes that sold out (the next section shows how).
2. Pre-order counts. Exact demand from committed buyers, covered in pre-orders vs in-stock drops.
3. A roster or sign-up form, when you are outfitting a defined group such as staff or a team.
4. A survey or waitlist that asks for size, which is weaker than money but better than nothing.
5. Sales of similar products from a stockist, a past merch table or a related brand you work with.
6. Judgment, weighted toward the middle sizes and kept lean at the edges, with a reorder planned in advance.

The cut of the garment changes the answer. In a boxy or oversized fit, some buyers size down; in a slim fit, some size up. Your product page's fit notes and size chart steer those choices too, so keep them consistent from release to release or your old data stops applying.

Worked example: correcting past sales for sizes that sold out

A brand ordered 120 tees for its last drop: 12 S, 30 M, 36 L, 30 XL, 12 2XL. Medium sold out on day four and Large on day six. After a month, 6 XL and 5 2XL were still on the shelf.

Raw totals mislead here, because Medium and Large stopped selling only because they ran out. The fix is to look at the period before the first size sold out, when every size was available. In the first three days the brand sold 50 tees:

The early sales give a curve of 4 : 16 : 18 : 9 : 3 per 50 units. Multiplied by three, it becomes the next order of 150. Compared with the first guess, Medium rises sharply even though XL falls, which matches what actually happened on the shelf.

Two cautions. Launch-day buyers are not always the same people as later buyers, so check that the sizes which never sold out kept roughly the same pattern over the following weeks. And three days is a small sample; with more history, use several drops.

Worked example: from pre-orders to a production order

A pre-order closes with 110 orders: 9 S, 31 M, 38 L, 22 XL, 8 2XL, 2 3XL. The brand wants two spares per size for misprints and exchanges, plus 20 extra units to sell in stock afterward, spread along the same curve.

The extra stock column is each size's pre-order count divided by 110, times 20, rounded. Notice that rounding leaves 3XL with no extra stock at all, which is usually right: the edge sizes are where leftovers pile up.

How the audience changes the curve

There is no universal curve, but there are questions worth asking for each kind of buyer:

• Staff and corporate orders (companies): do not guess. Collect sizes through a form before ordering, offer a fit sample or size chart with the form, and add a few spares in the middle sizes for new hires and mistakes.
• Teams, schools and clubs (sports teams, schools and clubs): a roster gives exact sizes. Youth sizes are separate garments, sometimes a different style, so confirm the blank comes in both.
• Bands and events (bands): there is no roster and every crowd differs. Fans also buy for partners and children. Record sizes sold per night and per city; within one tour that becomes the best data you have.
• Gyms and fitness brands (gyms): members may want fitted or women's cuts rather than unisex. Ask them, and treat each cut as its own run.
• Clothing brands: your chosen fit and how you describe it on the product page shape what people pick. If you change blanks, start the curve again rather than carrying the old one over.

Extended sizes and what they cost

Sizes 2XL and up are usually priced higher by blank makers, and some styles or colors stop at XL or 2XL altogether. Check availability for every color before you promise a size range. Print size is the other issue: one screen size across a run can look small on a 4XL and crowd a Small, so large designs are sometimes printed in two graded sizes, which jumbo and oversized prints explains.

Offering extended sizes is a decision about who your brand serves, and it is a good one to make deliberately. Keep those sizes lean in stock, restock them quickly, or sell them as a pre-order alongside in-stock core sizes. Decide up front whether they carry an upcharge, and run both options through pricing and margins.

Avoiding dead stock

Leftover Smalls and 3XLs tie up cash that should be paying for the next run. Habits that prevent it:

• Never order equal quantities across sizes. A flat run guarantees leftovers at both ends.
• Launch fewer colors. Each colorway needs its own size run, which multiplies the tails.
• Keep the first total modest and plan the reorder before launch, including who reorders, when and how fast it can land.
• Check that the blank will still be available for a reorder. Blank colors and stock risk covers discontinued colors and dye-lot changes.
• Review sell-through by size every week during a release, not after it ends.
• Move leftovers deliberately: bundles, merch tables, staff, giveaways. Constant discounting teaches buyers to wait.

Reorder points

A reorder point is the stock level at which you place the next order so new stock lands before the old runs out. The arithmetic:

Reorder point = units sold per week × weeks of lead time + safety stock

Lead time is the whole span from placing the reorder to having sellable stock: sourcing blanks, production, finishing, transit and receiving at your fulfillment location. Ask your printer for that timeline on each reorder rather than assuming it matches the first run.

In practice the fastest size usually triggers a reorder of the whole design, because screen setup and minimums make a one-size reorder expensive. When the trigger fires, recompute every size from current sell-through. For small top-ups of a single size, a lower-setup method such as DTG may make sense; screen printing vs DTG compares the two, and what drives screen printing cost explains why setup changes the math.

Size run checklist

• Curve built from the best data available, with sold-out sizes corrected
• One curve per cut (unisex, women's, youth), not one curve for everything
• Size range confirmed for every color of the chosen blank
• Spares added for misprints and exchanges
• Extended sizes priced and stocked on purpose
• Reorder point set for each size, with the printer's reorder lead time
• Weekly sell-through review on the calendar for the release

Useful for: clothing brands, bands, companies, sports teams.