The formula
GMROI = Gross Margin $ ÷ Average Inventory Cost
Gross margin dollars are your sales minus cost of goods sold over the period. Average inventory cost is the average value of the inventory you held to generate those sales, measured at cost (wholesale), not retail.
A worked example
Say a category did $200,000 in sales last year at a 55% gross margin, so it produced $110,000 in gross-margin dollars. Over the same year you held an average of $50,000 of that inventory at cost.
GMROI = $110,000 ÷ $50,000 = 2.20
Every dollar invested in that inventory returned $2.20 in gross margin. As a rule of thumb, a GMROI above 1.0 means the gross margin you earned exceeds the average cost value of the inventory you held to earn it — and the higher the number, the harder each inventory dollar worked.
Why GMROI beats margin percent alone
Margin percentage is seductive and incomplete. A 70%-margin item that sits for a year can be a worse investment than a 35%-margin item that turns six times, because the fast turner recycles your cash again and again. GMROI captures that by putting margin dollars over the capital actually tied up — so it rewards velocity and profitability together, which is exactly how a buyer should think about an open-to-buy dollar.
GMROI and inventory turns are the same story
GMROI decomposes neatly into the two levers a buyer controls:
GMROI ≈ Gross Margin % (on cost) × Inventory Turns
That’s why inventory turnover and GMROI are best read side by side. Turns alone ignore profitability; margin alone ignores speed; GMROI fuses them into one comparable number you can rank categories, vendors, and even individual styles by.
What’s a healthy GMROI?
There’s no universal “good” number, because GMROI swings with margin structure and turn speed: a high-margin, slow-turning category and a low-margin, fast-turning one can land in very different places and both be perfectly healthy. Rather than chase a borrowed benchmark, judge GMROI two ways that are always valid:
- Against your own trend. Is a category’s GMROI rising or falling over time?
- Against your other categories. Which parts of the store earn the most gross margin per dollar invested, and which tie up cash for little return?
Those two comparisons are grounded in your actual costs, margins, and turns — which makes them far more useful than any one-size-fits-all figure.
How to improve GMROI
- Buy to turn. Smaller, more frequent commitments recycle cash faster and lift the turns half of the equation.
- Protect margin. Negotiate cost, control freight in your landed cost, and time markdowns so you clear without giving away more than you must.
- Kill dead stock. Aged inventory inflates average inventory cost and earns almost no margin — the worst possible GMROI input. See dead stock.
- Reorder with discipline. Reorder rules and demand signals keep winners in stock without over-committing capital.
GMROI in Vendee Pro
Vendee Pro’s Report Studio surfaces GMROI alongside inventory turns and Cash Margin ROI (CMROI), grouped by category, vendor, supplier, or source — so you can rank where your inventory dollars are actually working. Inventory feature →
Frequently asked questions
What is a good GMROI?
A GMROI above 1.0 means the gross-margin dollars you earned exceed the average cost value of the inventory you held to earn them. There’s no universal target — it depends on your category, margin structure, and turn rate — so judge it against your own history and against how your categories rank relative to each other rather than a borrowed number.
What’s the difference between GMROI and gross margin?
Gross margin is a percentage of sales and ignores how much cash is tied up in stock. GMROI divides gross-margin dollars by the average inventory investment, so it rewards products that earn margin quickly on a small amount of capital and penalizes high-margin items that sit.
How is GMROI related to inventory turnover?
GMROI is roughly gross-margin percent multiplied by the cost-based turn rate, so turns and margin both drive it. A slow-turning, high-margin item and a fast-turning, low-margin item can produce the same GMROI.
How do I improve GMROI?
Raise margin (better buying, smarter markdowns), turn faster (smaller, more frequent buys and disciplined reorders), and cut the dead stock that drags down average inventory. Improving any of the three lifts GMROI.
Rank your inventory by GMROI.
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