Retail assortment planning is deciding, before you buy, how your inventory budget splits across categories, price points, styles and units. It is the difference between a boutique that looks intentional and one that looks like a collection of things somebody liked at market.
I am Carina Hatton, boutique owner since 2013 and ecommerce coach since 2019. This guide covers the decisions in the order you actually make them: budget, categories, price points, width, depth, sizes and colours. Every dollar figure is a clearly labelled hypothetical rather than a benchmark.
Quick answer
What assortment planning actually means
An assortment is the full set of products you offer in a period. Assortment planning is the process of deciding its shape in advance: which categories, at which price points, in how many styles, with how many units behind each one, arriving when.
Most small boutiques skip it and buy reactively, then wonder why the floor has fourteen tops in the same shade and nothing to wear them with. Planning does not remove taste from buying. It gives taste a budget and a shape to work inside.
Width versus depth
| Term | What it means | Too much of it looks like | Too little looks like |
|---|---|---|---|
| Width (breadth) | How many different styles you carry | A sample sale. One of everything, nothing available in her size | A thin, repetitive floor with nothing to discover |
| Depth | How many units of each style | Cash locked in one bet and a markdown rail in month five | Sold out of the winner in week two with no reorder |
Width and depth compete for the same dollars, which is the whole tension of buying. The resolution is not a magic ratio, it is evidence: go wide where you are learning, go deep where you already know. The unit-level arithmetic is in how many units per style to buy and the style count question is in how many styles to start with.
Start with the budget, not the products
- Set the total. For an existing store this is open-to-buy for the period, covered in open-to-buy for small boutiques. For a new store it is the opening inventory budget, covered in how much inventory to start a boutique.
- Remove a reorder reserve. Committing every dollar up front means you cannot chase what sells, which is the most profitable thing a buyer ever does.
- Split by category. Use your own sell-through history if you have it, or a deliberate plan if you do not.
- Split by price band inside each category. This is the step most people skip and most regret.
- Convert dollars into styles and units. Only now do you know how many things you are actually buying.
Category planning
Categories are how a customer shops and how you should budget. For an apparel boutique the usual split is tops, bottoms, dresses, outerwear, accessories and gift. Three rules that hold up:
- Every category needs a job. Traffic driver, margin builder, add-on, gift, or basket filler. A category with no job is a category absorbing budget for no reason.
- Categories must connect. If nothing in the store goes with the dresses, the dresses sell alone and the basket stays small.
- Accessories pull above their weight. They are usually lower cost, simpler to store, size-free, and they lift average order value. Planning help is in wholesale accessories for boutiques.
Price-point planning
Every category needs a spread of price bands so a customer can enter at a comfortable level and trade up.
| Band | Role in the assortment | Buying implication |
|---|---|---|
| Entry and impulse | Easy first purchase, counter add-on, gift | Low cost, high unit count, minimal size complexity |
| Core | The bulk of sales and the store's identity | Deepest buys, strongest reorder relationships |
| Elevated | Aspiration, occasion, standout pieces | Shallow buys, high margin dollars, longer selling window |
A floor with only core pricing has nothing for a browser to grab and nothing for a special occasion. Set the bands from what your customer actually pays, not from what you wish she paid, and check the arithmetic against retail pricing and landed cost.
Core versus trend inventory
| Factor | Core | Trend |
|---|---|---|
| Purpose | Reliable sales and a recognisable store identity | Newness, content, reasons to visit again |
| Depth | Deeper, because it sells predictably | Shallow, because the window is short |
| Reorder | Reorder aggressively while it performs | Rarely worth chasing once the moment passes |
| Markdown risk | Lower, it holds value across seasons | High, plan the markdown date at purchase |
| Carrying cost exposure | Manageable | Expensive if it lingers. See inventory carrying cost |
Online boutique versus storefront
| Consideration | Online | Storefront |
|---|---|---|
| Width constraint | Photography and listing time, not shelf space | Fixtures and floor space are a hard limit |
| Depth pressure | A sold-out size looks like a dead page | A gap on a rail is less visible to the customer |
| Size runs | Broken runs hurt conversion badly | Easier to sell around a missing size in person |
| Impulse items | Work as cart add-ons and bundles | Work at the counter and near the fitting room |
| Newness cadence | Frequent small drops keep the audience engaged | Floor resets and window changes carry the same job |
Size runs and colour choices
Sizes and colours multiply. One style in five sizes and three colours is fifteen SKUs, each of which must be received, counted, merchandised and eventually sold. That multiplication is why SKU discipline matters, covered in how many SKUs a small boutique should carry.
- Buy depth in the middle of your own size curve, based on your sales history rather than the vendor's prebuilt run.
- Ask whether a run can be broken. Sometimes it can, and nobody asks.
- Limit colours per style on unproven product. Two colours tells you what three tells you, at two thirds of the risk.
- Plan the palette across the buy, so separates coordinate and outfits build themselves on the floor.
- Record the run you bought, so you can compare it to what sold when you review.
Minimums, case packs and test buys
Vendor minimums push against your plan constantly. A prebuilt pack is the vendor's assortment decision arriving inside yours.
- Check the per-style minimum and the per-order minimum separately. Both can force overbuying.
- Price the whole pack, not the unit. If you cannot see yourself selling every unit at full price, the pack contains a markdown.
- Use the smallest viable test buy on new vendors, sized so you can still read a result.
- Prefer vendors with fast reorders when you are testing, because speed lets you buy shallow safely.
Background on minimums is in minimum order quantity, and splitting a first order across categories is in how to split your first wholesale order.
Worked hypothetical assortment examples
Illustrations only. Neither is a recommendation, and both assume an apparel-led boutique with some accessories.
Smaller budget: $6,000 inventory spend
| Category | Budget | Styles | Average units per style | Notes |
|---|---|---|---|---|
| Tops | $1,800 | 9 | 10 | Core of the floor, mid depth |
| Bottoms | $1,200 | 4 | 10 | Fewer styles, full size runs |
| Dresses | $1,050 | 5 | 7 | Occasion and everyday split |
| Accessories | $750 | 12 | 6 | Wide, shallow, size-free |
| Reorder reserve | $1,200 | n/a | n/a | Untouched until sell-through data exists |
A tighter budget should be narrower rather than shallower. Thirty styles at three units each fails in both directions at once.
Larger budget: $18,000 inventory spend
| Category | Budget | Styles | Average units per style | Notes |
|---|---|---|---|---|
| Tops | $5,400 | 22 | 12 | Core depth plus a trend slice |
| Bottoms and denim | $3,600 | 10 | 12 | Complete size runs matter most here |
| Dresses | $2,700 | 12 | 8 | Seasonal, markdown dates set at purchase |
| Outerwear | $1,800 | 4 | 6 | High ticket, shallow, long window |
| Accessories and gift | $1,800 | 25 | 8 | Impulse and add-on price points |
| Reorder reserve | $2,700 | n/a | n/a | Deployed on proven sell-through |
Note what grew and what did not. The larger budget added width in accessories and depth in core apparel, and kept outerwear shallow because a high-ticket category ties up a lot of cash per unit.
Avoiding a floor that feels thin
- Fewer styles bought properly beat many styles bought thinly. Presentation depends on multiples.
- Group by outfit and colour story rather than by vendor, so a small buy reads as a collection. More on this in visual merchandising.
- Use accessories and gift to fill visual space cheaply while apparel budget goes to depth.
- Keep some open space deliberately. A packed rail is not the same thing as a full assortment.
Avoiding SKU proliferation
- Every SKU costs receiving time, counting time, shelf space and holding cost forever.
- Cap colours per style on unproven product.
- Retire underperformers deliberately, on a schedule, rather than waiting for them to embarrass you.
- Ask what each new SKU replaces. If the answer is nothing, the assortment is drifting wider by accident.
Using sales history for the next buy
- Review sell-through by style at two and four weeks after delivery.
- Roll it up by category and price band, which is where the buying lesson actually lives.
- Check size sell-through separately, and adjust the run you request next time.
- Score vendors on sell-through, delivery reliability and reorder speed.
- Feed all of it into the next open-to-buy rather than into your memory.
Two review points beat one annual reckoning, because week four is when a reorder is still possible and a markdown is still cheap.
Reorder planning and markdown risk
Every assortment plan needs two dates attached to each style: when you would reorder it, and when you would mark it down.
- Reorder trigger: a sell-through threshold you set in advance, checked against lead time using the Reorder Point Calculator.
- Markdown trigger: a date or an age threshold, decided at purchase rather than when the rail looks tired. Work the depth of discount in the Markdown Calculator.
- Reserve deployment: spend the reorder reserve on evidence, in the window where reordering still helps.
Assortment planning does not end when the order is written. It ends when the stock has cleared and the result has changed the next plan. Keep the whole loop inside your standing routine with boutique inventory management.
Planning the assortment across the year
A plan that covers one buy is a shopping list. A plan that covers the year is an assortment plan. The difference is that the second one leaves money for the months you have not bought yet.
Split the annual inventory budget across the buying periods you actually use, then hold a reserve inside each one. A common shape is to commit the majority of a period's budget to planned categories, leave a portion for reorders on whatever sells, and keep a small amount for opportunities. The reserve is what lets you repeat a winner, which is almost always a better use of money than adding another untested style.
| Purpose | Share of the period budget | What it buys |
|---|---|---|
| Planned assortment | Largest share | The categories and price points the plan calls for |
| Reorder reserve | Meaningful second share | Depth on styles that have already proven themselves |
| Opportunity and test | Smallest share | New categories or vendors, bought shallow |
Set the actual percentages from your own sell-through history rather than a rule. A store whose reorders consistently outperform new styles should weight the reserve heavier. Size each period against your monthly capacity using open-to-buy for small boutiques.
Reviewing the plan so the next one is better
- Review by category, not by style. One bad dress tells you little. A category that consistently underperforms tells you the plan was wrong, not the buy.
- Compare planned versus actual spend. If you routinely overspend one category, either the plan is unrealistic or the discipline is.
- Track how much of the budget went to reorders. A rising share usually means the buying is getting sharper.
- Note what you ran out of. Stockouts on core product are a planning failure, even though they never appear as a loss anywhere.
- Record price-point results. If nothing above a certain price sells, that ceiling belongs in the next plan.
Do this once per buying period and write the conclusions somewhere you will actually read before the next market. An assortment plan improves through repetition and honest review, not through a better template.