Year-over-Year (YoY) growth is a key performance metric in e-commerce that compares a business metric (such as revenue, traffic, or orders) in one period to the same period in the previous year. YoY analysis removes seasonal fluctuations and provides a clearer picture of long-term business trends, helping e-commerce managers make strategic decisions about inventory, marketing spend, and expansion.

In beauty e-commerce, tracking YoY growth is essential for evaluating the success of product launches, seasonal campaigns, and loyalty programs. For example, comparing Q4 holiday sales year-over-year reveals whether a brand’s gift set strategy is gaining traction, while normalizing for seasonal spikes in categories like sunscreen or holiday palettes.