GMROI Calculator
Gross margin return on inventory investment, GMROI, answers the question every retailer should ask of each product: how hard is this inventory working for me? It pairs the margin you earn with the capital you have tied up in stock, so a product is judged on both profitability and how efficiently it sells through. A GMROI above 1 means the inventory earns back more than it costs. Enter your gross margin dollars (sales minus cost of goods sold) and your average inventory at cost, and this calculator returns GMROI, the gross margin percentage, and the gross margin earned per dollar of stock.
GMROI formula
Gross margin = net sales - cost of goods sold
GMROI = gross margin / average inventory at cost
Gross margin % = (gross margin / net sales) * 100
GMROI shows how many gross margin dollars each dollar of inventory generates. A value above 1.0 means the inventory earns back more than its cost.
Using GMROI
- A GMROI above 1.0 means inventory is generating more margin than it costs to hold.
- Compare GMROI across product categories to spot underperforming stock.
- Fast turnover lifts GMROI even at modest margins.
- Value inventory consistently at cost when computing the average.
- Use the same period for sales, cost of goods, and average inventory.
GMROI: frequently asked questions
What is GMROI?
GMROI stands for gross margin return on inventory investment. It measures how many gross margin dollars a retailer earns for each dollar invested in inventory at cost. A GMROI of 3.0 means every US$1 tied up in inventory generates US$3 of gross margin over the period.
How is GMROI calculated?
GMROI equals gross margin dollars divided by the average inventory at cost. Gross margin dollars is net sales minus cost of goods sold. Average inventory at cost is typically the average of beginning and ending inventory valued at cost over the same period.
What is a good GMROI?
A GMROI above 1.0 means the inventory generates more gross margin than its cost, which is the minimum for the inventory to be worthwhile. Many retailers target a GMROI well above 2.0, but healthy levels vary widely by category, turnover, and margin structure.
Why use GMROI instead of margin alone?
Margin alone ignores how much capital is tied up in stock and how fast it sells. GMROI combines margin and inventory efficiency, so a low-margin, fast-turning product can outperform a high-margin product that sits on the shelf. It is a truer measure of inventory productivity.
How does inventory turnover relate to GMROI?
GMROI can be seen as gross margin percentage on sales multiplied by the sales-to-inventory ratio. Faster turnover raises GMROI for a given margin, which is why managing both price and stock levels matters for inventory return.
Official sources
- U.S. Small Business Administration: Manage your finances.
- U.S. Census Bureau: Monthly Retail Trade.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.