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GMROI: Gross Margin Return on Investment Explained [2026]
You can be profitable on paper and still run out of cash. It happens to growing sellers all the time: margins look healthy, sales are climbing, yet the bank balance keeps shrinking because too much money is tied up in stock that turns too slowly. GMROI is the one metric that exposes this. It answers a deceptively simple question: for every dollar you sink into inventory, how many dollars of gross margin do you get back? Most sellers track margin and they track turnover, but GMROI fuses the two into a single figure that tells you whether your inventory is actually earning its keep. This guide explains what GMROI means, how to calculate it with a real worked example, what a good score looks like, and the practical levers you can pull to improve it across every marketplace you sell on.