How to build a buy plan for apparel
A buy plan is the line-by-line plan of what you will purchase for a season — quantities, costs, retail, margin, channel split, sizing, and delivery timing — built from your assortment plan and kept inside your open-to-buy. You build it by starting with the financial guardrails, translating the assortment into planned buys, layering in cost and timing and sizing, validating against OTB, and converting the result into purchase orders.
The eight steps below take a buy plan from budget to purchase orders to receipts.
Start with financial guardrails
Begin from your open-to-buy and the season’s sales and margin targets. OTB sets the ceiling on how much stock you can commit; the buy plan has to live inside it. Establish the budget by category and period before you plan a single unit.
The open-to-buy calculator works out how much budget is left to commit.
Translate assortment into planned buys
Take the agreed assortment — the options by channel and their planned depth — and turn it into a line-by-line list of what you intend to buy. Each row is a style/colour with a planned quantity that reflects the role it plays in the range.
Start from the assortment planning template to carry option and depth decisions into the buy.
Add cost, retail, and margin
Attach cost price, planned retail, and the resulting margin to every line. Roll it up to confirm the blended margin meets the season target, and adjust depth or price where it does not.
Add channel and timing
Split planned quantities across channels and place them on a delivery timeline. Phasing intake to demand keeps cover sensible and protects full-price selling rather than landing everything at once.
Add sizing
Break each planned buy down to size level using a size curve so the quantities you order match how the style actually sells by size, not an even split.
Use the size curve calculator to split each buy into size-level quantities.
Validate against OTB
Roll the full buy plan back up and check it against open-to-buy by category and period. Where the plan exceeds budget, trim depth, drop options, or shift timing until the buy fits the financial guardrails.
Convert to purchase orders
Turn the approved buy plan into purchase orders by vendor, with quantities, costs, sizing, and delivery dates carried through so the PO matches the plan exactly.
Track production and receipts
Follow each PO through production and into receipts, comparing what lands against what was planned. Late or short deliveries change cover, so feeding receipts back keeps the in-season plan honest.
Download the buy plan template to lay out the worksheet in Excel before moving to a connected workflow.
Frequently asked questions
- What is a buy plan?
- A buy plan is the line-by-line plan of what an apparel team will purchase for a season — quantities, costs, retail prices, margin, channel split, sizing, and delivery timing — built from the assortment plan and constrained by open-to-buy. It is the bridge between the assortment and actual purchase orders.
- What is the difference between an assortment plan and a buy plan?
- The assortment plan decides what options to offer, where, and at what depth. The buy plan converts those decisions into concrete purchase quantities with costs, margin, sizing, and delivery timing, validated against open-to-buy. The assortment plan is the intent; the buy plan is the commitment.
- How does open-to-buy fit into a buy plan?
- Open-to-buy is the budget guardrail the buy plan must fit inside. You start from OTB to know how much you can commit, build the buy plan, then validate the total back against OTB by category and period before converting it to purchase orders.
- Do I need a size curve to build a buy plan?
- For apparel, yes — a size curve translates total style/colour quantities into size-level buys so you order the right depth per size instead of an even split. Without it, you over-buy fringe sizes and under-buy core sizes, which drives early stock-outs and end-of-season markdown.
- A buy plan turns assortment decisions into line-by-line quantities, costs, retail, and margin.
- Start from open-to-buy so the plan lives inside the season’s financial guardrails.
- Layer in channel split, delivery timing, and size curves so depth matches real demand by size.
- Validate the rolled-up plan against OTB by category and period before converting to purchase orders.
- RetailNorthstar carries the buy plan through to POs, production, and receipts in one connected workflow.
See how RetailNorthstar connects buy plans to OTB, sizing, POs, and production.