GMROI Calculator (Gross Margin Return on Investment)

GMROI (Gross Margin Return on Investment) is a retail and merchandising metric that answers a simple question: for every dollar tied up in inventory, how many dollars of gross profit does that inventory generate? It's calculated by dividing gross margin (Net Sales − Cost of Goods Sold) by the average inventory cost — inventory valued at what it cost to buy or produce, not at retail price. A GMROI of 2.5 means every $1 invested in stock returns $2.50 in gross profit; a GMROI below 1 signals the inventory is generating less gross profit than it cost to carry. GMROI can also be broken into two components — GMROI = Gross Margin % × Inventory Turnover (at cost) — which shows that the same GMROI can come from either high margins with slower-turning stock, or thin margins with fast-turning stock. Retailers and category managers use GMROI to compare product lines, vendors, or SKUs that carry very different margins and turnover rates, since neither margin nor turnover alone tells the full profitability story. This calculator supports three ways to get to a GMROI figure — from net sales, COGS, and average inventory cost directly, from beginning and ending inventory balances, or from a known gross margin percentage and inventory turnover ratio. For a broader look at return on any capital investment, see the ROI calculator.