How to Stock the Right Size Ratios (So You’re Not Stuck with Broken Inventory)

Stock Smart: Why Size Ratios Matter More Than You Think

Every retailer knows the frustration: you've got shelves full of inventory, but customers keep walking out empty-handed. The problem isn't always what you're selling—it's often how much of each size you're carrying. You might have styles your clients love, strong brands, and great merchandising, but if you’re missing key sizes, you’re leaving revenue on the table every single day.

When your inventory becomes broken—meaning key sizes are sold out—you’ll notice sell-through slow down immediately. Clients are less likely to browse, conversion rates drop, and you may feel pressure to mark down remaining units just to move them. This is where margins start to erode. Instead of driving revenue, your inventory starts working against you.

Broken inventory isn't just unsold merchandise. It's capital tied up in products that don't match customer demand, shelf space wasted on sizes nobody wants, and the constant pressure to discount or liquidate stock just to free up room. The good news? Getting your size ratios right is one of the most powerful levers you have to improve profitability and customer satisfaction at the same time.

Understanding Your Customer's Size Distribution

The first step is knowing what your customers actually buy. Every product category, brand, and customer base has a different size distribution. Many studios either guess their size breakdown or default to standard wholesale packs without thinking about their specific client base. But not all studios sell evenly across sizes. A fashion style might skew heavily toward specific sizes, while a mainstream product spreads more evenly across the range. 

Start by analyzing your historical sales data. Look at which sizes sell fastest, which ones linger, and which ones never move at all. Most retailers find that 20% of their sizes generate 80% of their sales—and the remaining inventory becomes a liability. Track this data by product category, season, and customer segment. The patterns will tell you exactly where to focus your buying power.

The Cost of Getting It Wrong

Overstocking unpopular sizes creates a cascade of problems. You lose margin when you mark down slow-moving inventory. You tie up cash that could go toward bestselling sizes or new products. You waste warehouse or shelf space on items that don't convert. And you frustrate customers who can't find their size because you're holding too much of everything else.

Understocking popular sizes is equally damaging. You miss sales, disappoint customers, and often lose them to competitors who have stock available. You also send a signal to your suppliers that demand is lower than it actually is, which can affect future allocation and pricing.

Building a Smarter Buying Strategy

Once you understand your size distribution, use it to guide every purchase order. Allocate your budget proportionally to demand. If size medium represents 35% of your sales, it should represent roughly 35% of your next order—not 20% because you have leftover inventory from last season.

Work closely with your vendors to negotiate flexible ordering. Ask about split shipments, pre-season adjustments, or the ability to reorder bestselling sizes mid-season. Many suppliers will work with you if you show them data-driven demand patterns instead of guessing.

Monitoring and Adjusting in Real Time

Your size ratio strategy isn't set-and-forget. Use your point-of-sale system and inventory management tools to track performance weekly or monthly. Identify sizes that are selling faster than expected and sizes that are stalling. When you spot a trend, act on it quickly—reorder bestsellers before they're gone, and consider markdowns or promotions on slow movers before they become dead weight.

Set clear thresholds for action. If a size drops below a certain inventory level, trigger a reorder. If a size hasn't sold in 60 days, plan a promotion or clearance. Proactive management prevents small problems from becoming big ones.

The Bottom Line

Carrying the right size ratio isn't about stocking everything equally. It's about aligning your inventory with actual customer demand, protecting your cash flow, and maximizing the productivity of every dollar and every square foot of space you have. When you get it right, you reduce waste, improve margins, and create a better shopping experience for your customers. That's the foundation of sustainable retail growth.

If you want to take the guesswork out of this entirely, using a size curve calculator can help you map out exactly how many units to buy in each size based on your total units and sales mix. This ensures you’re optimizing every dollar of inventory you invest—so you’re not stuck with excess in the wrong sizes while your best sellers are sold out.