More things per bag.

The other way up

An order's value is price times quantity, which leaves exactly two ways to raise it: sell pricier things, or sell more of them. UPT tracks the second. It is AOV's sibling, counted in units instead of dollars, and the two are only useful read together — if AOV climbed ten percent, UPT tells you whether shoppers traded up to dearer items or simply put more in the bag. Growth from quantity behaves differently from growth from price: it usually costs a discount, and it usually ships heavier. Most stores hover surprisingly close to one unit per order, which is exactly why the metric is worth watching — the gap between 1.2 and 1.6 is bought with merchandising, not traffic.

What lifts it

Anything that gives the second item a reason to exist. Bundles price the pair below the sum of its parts. BXGY offers go further and make the extra unit the reward itself — buy two, get the third free is a UPT lever wearing a discount's clothes. A free-shipping threshold set just above your typical order turns shipping into the nudge: one more small thing and it ships free. And "complete the set" cross-sells — the lens with the camera, the filter with the machine — work because they finish a thought the shopper already had. Whichever you pull, keep watching the pair of numbers: if UPT rises while AOV stands still, the extra units came entirely out of the price.