What a size curve is
A size curve is the share of units you plan to buy in each size. It turns a total quantity into a size-by-size order. A curve that matches your customers sells through evenly; one that does not leaves you with slow sizes and stock-outs in the sizes that move.
Build the curve from your own data
- Export last season’s sales by size for the style or a similar one.
- Convert units sold in each size to a share of the total.
- Adjust for channel: online customers and store customers often buy different size mixes, and returns by size show where the fit chart misleads.
- Round to quantities that suit the pack format and the cartons.
- After the first sell-through, update the curve and reorder.
If you have no data, start with a balanced curve and plan to correct it. The two curves below are examples of the arithmetic, applied to 1,200 pieces of one style in one colour.
| Size | Balanced curve | Pieces | Extended-size curve | Pieces |
|---|---|---|---|---|
| S | 10% | 120 | 5% | 60 |
| M | 30% | 360 | 20% | 240 |
| L | 30% | 360 | 28% | 336 |
| XL | 20% | 240 | 25% | 300 |
| XXL | 10% | 120 | 15% | 180 |
| 3XL | – | – | 7% | 84 |
| Total | 100% | 1,200 | 100% | 1,200 |
Colour splits
Start with a small number of core colours. Every colour is a separate fabric lot and, for many suppliers, a separate minimum. The matrix below applies the balanced curve to three colours at 1,200 pieces each.
| Colour | S | M | L | XL | XXL | Total |
|---|---|---|---|---|---|---|
| Colour 1 | 120 | 360 | 360 | 240 | 120 | 1,200 |
| Colour 2 | 120 | 360 | 360 | 240 | 120 | 1,200 |
| Colour 3 | 120 | 360 | 360 | 240 | 120 | 1,200 |
| Total | 360 | 1,080 | 1,080 | 720 | 360 | 3,600 |
Pack formats
| Format | Often used for | Plan for |
|---|---|---|
| Single piece | Premium or single-style listings | Individual polybag or box, barcode on each piece |
| 2-pack | Value bundles | Pack artwork, mixed or same colour |
| 3-pack | Retail shelves and online bundles | Colour assortment per pack, barcode per pack |
| 5- or 6-pack | Value and club programs | Carton count and weight, pack artwork |
Decide whether each pack contains one colour or an assortment, and whether every pack holds a single size. Assorted packs change how the colour split is counted: three-piece packs with one piece of each of the three colours above and one size per pack mean the 360 size-S pieces become 120 packs.
Count pieces and packs the same way everywhere
Write the order in pieces and state the pack size, so that 3,600 pieces in three-piece packs is 1,200 packs. Ask for pieces per carton and carton count on the quotation, because purchase order, packing list and invoice must match. A mismatch between pieces and packs is a common source of shipment-document corrections.
Reorders and consistency between lots
- Reorder from sell-through by size, not from the first order’s curve.
- Keep the approved sample as the reference for every reorder.
- Ask how shade differences between dye lots are controlled, and approve a shade band or a lot-to-lot standard.
- Re-confirm materials, quantity and timing for each reorder rather than assuming the first order’s terms still apply.
What to put in the RFQ
- Quantity by style, colour and size, using the matrix format above.
- Pack format, assortment and barcode requirements.
- The minimum-counting question: per order, style, colour or size.
- Destination and requested delivery date.
- Whether you need samples before ordering.
The RFQ and supplier comparison workbook on the OEM page includes a style, colour and size quantity matrix with totals, which you can reuse for a wholesale order.
Common questions
What size curve should a new brand start with?
There is no universal curve. If you have no sales data, start with a balanced curve such as the first example and plan to correct it after the first sell-through.
Is it better to order fewer colours or fewer sizes?
Fewer colours usually reduce fabric-lot minimums, while dropping sizes risks stock-outs and returns. Start with a few core colours and the full size run your customers need.
Can you pack assorted colours in one multipack?
Yes, assorted packs are common. Specify the colours per pack, the pack size and the packaging format, and ask the quotation to state how pieces and packs are counted.
Ready to brief a style?
Send a reference garment or sketch, the quantities you are considering and your destination. The quotation will state what is included and how minimums are counted.