Diapers Size 4 Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

Pampers is the best-performing diapers size 4 brand in July 2026, moving 79,000 units across 5 ASINs for 66.9% of Top 10 volume. HUGGIES follows with 32,000 units (27.1%), ahead of Pull-Ups on 7,000 units (5.9%).

With 3 brands splitting the Top 10 and 100.0% of volume sitting with three of them, this is a concentrated shelf — the leaders hold multiple listings or one very high-velocity ASIN, so a new entrant competes against established review moats rather than an open field. Average selling prices among the leaders run from $29.97 to $40.75, which frames the price band a competing listing has to justify.

Based on July 2026 data, this shortlist surfaces the two kinds of ASIN worth keeping an eye on — the ones that just broke into the Top 10, and the ones growing fastest month over month. Specifically, one ASIN forced its way in: B08QRHGCWQ booked 5K units at $28.49, with ▼ 16.7% MoM change. On the growth side, B0GQSDLQ55 leads positive momentum with ▲ 900.0% MoM growth on 1K units, with B07H34Q5S5 close behind at ▲ 122.2% MoM on 2K units.

The two signals carry different weight. A fresh entrant means share has already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date. A steep growth rate works as the earlier warning: it marks demand that is still compounding, usually a month or two before the ranking catches up to it.