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GMROI Ratio
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A GMROI calculator works out your gross margin return on investment: how many dollars of gross margin you earn for every dollar tied up in inventory. It fuses two numbers sellers usually track separately, your margin and your stock turnover, into one figure that tells you whether your inventory is genuinely earning its keep. For ecommerce sellers running hundreds of SKUs across Shopee, Lazada, TikTok Shop, Amazon, and Shopify, GMROI is the fastest way to spot which products deserve more reorder budget and which are quietly draining your cash. For the full concept, worked examples, and benchmarks, read our complete guide to GMROI.
The formula is: GMROI = Gross Margin ($) / Average Inventory at Cost. Your gross margin in dollars is net sales minus cost of goods sold. Average inventory must be valued at cost, the price you paid your supplier, not the retail price you sell at. This calculator does both steps for you: it derives gross margin dollars from your sales and COGS, then divides by your average inventory at cost. A GMROI of 3.0 means every $1 of stock returns $3.00 of gross margin over the period.
As a rule of thumb, a GMROI above 1.0 means the product earns more margin than it costs to hold. Below 1.0, that inventory is losing money. Most healthy retailers aim for 3.0 or higher, though the target varies sharply by category: high-margin, slow-turning goods like furniture can be healthy nearer 1.5, while fast-moving accessories and consumables should clear 3.0 comfortably. Always benchmark GMROI within a category, never across unrelated ones. Set a floor per category and flag every SKU that falls below it.
Inventory turnover tells you how fast stock sells; gross margin tells you how profitable each sale is. GMROI blends both, so a low-margin product that turns quickly can beat a high-margin one that sits on the shelf. Use our inventory turnover calculator for the velocity side and our profit margin calculator for the margin side, then bring both together here. If you need the cost figure first, our COGS calculator covers that input.
Because GMROI is margin dollars over inventory cost, you lift it by raising margin, cutting the cost you pay, or turning stock faster. The highest-leverage move is rebalancing your open-to-buy: once you know GMROI per SKU, shift reorder budget from low scorers to high scorers. Clearing dead stock decisively and negotiating better supplier terms both help too. The GMROI guide breaks down each lever with examples.
GMROI is only as good as your data. OneCart unifies inventory, orders, and per-channel margins across Shopee, Lazada, TikTok Shop, Amazon, and Shopify into one dashboard, so you see profitability per SKU without rebuilding the math each month.
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