Same shelf price. Less product.

SKU stands for "Stock Keeping Unit." It's the identifier a retailer uses to track a specific product on its shelves. A 10-ounce bag of Doritos and a 9.5-ounce bag of Doritos are two different SKUs — even though they look almost identical on the shelf. When a manufacturer shrinks a product, they create a new SKU, and the old one quietly disappears.

Why manufacturers use SKUs: SKUs let retailers manage inventory, track sales, and reorder products. But they also make it easy for manufacturers to change a product's size without drawing attention. The new SKU has a new barcode and a new weight, but the same brand name, same packaging design, and — crucially — the same shelf price. Most shoppers never compare the old SKU to the new one.

Why SKU-level tracking matters: If you only look at shelf prices, shrinkflation is invisible. The price didn't change — so inflation appears to be zero. But the price per ounce went up. A bag that was $4.99 for 10 ounces ($0.50/oz) is now $4.99 for 9.5 ounces ($0.53/oz) — a 5% effective price increase that doesn't show up in any headline number. Tracking at the SKU level — comparing the old size to the new size — is the only way to measure this hidden inflation accurately.