What is Assortment Planning in Retail?

What is assortment planning? Assortment planning means choosing the mix of products and variations you will offer in a specific season, location, or channel, and aligning that mix with sales and margin targets.

It focuses on balancing breadth (how many categories you carry) and depth (how many options in each category) so the assortment is focused but still interesting for customers. For fashion retailers, assortment planning usually runs by season.

Buyers and merchandisers use trend insights and sales history to decide which styles to buy, which colors and sizes to run, how many units to invest in, and what price ladder to build. The goal is a clear, data-backed range instead of reactive buying.

Why it matters for growth Assortment planning sits at the center of revenue, margin, and cash flow. A planned assortment reduces overstocks and markdowns because inventory is aligned more closely with demand…