What is sell-through rate and how do I calculate it for my boutique?

Sell-through rate tells you what percentage of each style you have actually sold since it arrived in your store. The formula is simple: units sold divided by units received, multiplied by 100. A style where you received 20 units and sold 14 has a 70% sell-through rate.

This metric is the clearest signal of whether a style is healthy or falling behind. A style at 30% sell-through halfway through summer needs a very different response than one sitting at 70%. Industry benchmarks from sources like Toolio and SPS Commerce recommend targeting 80–90% sell-through by the end of your summer selling window. Anything below 70% by Labor Day typically means you over-bought or waited too long to take markdowns.

Calculate this number for every summer SKU and update it weekly. It becomes the foundation for deciding which styles need discounting and which should be left at full price.