Basic GMROI
Each Rp1 of average inventory cost generates Rp2 or more of gross margin. This pattern usually comes from a combination of large margins and/or fast inventory turnover; the figure still needs to be read with its product-category context.
The results above are educational estimates, not investment advice. A single period’s GMROI figure is not enough to judge a business.
GMROI from margin% × inventory turnover
The second form of the GMROI formula: GMROI = gross margin (%) × inventory turnover, where inventory turnover = sales ÷ average inventory cost. This form is mathematically identical to (sales − COGS) ÷ average inventory cost.
Consistency with Mode 1: 40% margin × 5.0× turnover = 2.0× — exactly equal to (Rp1,000,000 − Rp600,000) ÷ Rp200,000 = 2.0×.
Solver: target GMROI → find the missing variable
Enter the target GMROI and two of three variables; the calculator finds the third from target = (sales − COGS) ÷ average inventory cost.
With Rp400,000 gross margin and a 3.0× target GMROI.
GMROI Comparator: product A vs product B
Frequently asked questions about GMROI
What is GMROI?
GMROI (Gross Margin Return on Investment) is a retail metric measuring inventory productivity: how many rupiah of gross margin are generated per rupiah of average inventory cost. A GMROI of 2.0 means each Rp1 of average inventory cost generates Rp2 of gross margin in the measured period. This metric is popular in retail because inventory is usually a store’s largest capital investment.
What is the GMROI formula? (two forms)
First form: GMROI = (sales − COGS) ÷ average inventory cost. Example: sales of Rp1,000,000, COGS of Rp600,000, and average inventory cost of Rp200,000 give gross margin of Rp400,000, so GMROI = Rp400,000 ÷ Rp200,000 = 2.0×.
Second form: GMROI = gross margin (%) × inventory turnover, where inventory turnover = sales ÷ average inventory cost. With the same figures: 40% gross margin × 5.0× turnover = 2.0× — identical to the first form, because (gross margin ÷ sales) × (sales ÷ inventory) = gross margin ÷ inventory.
What is the difference between GMROI, ROI, and gross margin (%)?
All three use a similar numerator but different denominators. Gross margin (%) = gross margin ÷ sales — measures what percent of sales becomes margin (example above: 40%). GMROI = gross margin ÷ average inventory cost — measures inventory productivity (example above: 2.0×). ROI (return on investment) = profit ÷ total invested capital — broader in scope because it uses all capital, not just inventory.
How does GMROI differ from inventory turnover and DIO?
Inventory turnover = sales ÷ average inventory cost — measures how many times inventory turns over in one period (example above: 5.0×). It is one of the two factors forming GMROI (GMROI = margin% × turnover). DIO (days inventory outstanding) = average inventory ÷ COGS × 365 — measures how many days inventory sits before being sold; with the example figures above, DIO = Rp200,000 ÷ Rp600,000 × 365 ≈ 121.7 days. GMROI assesses inventory from the margin-generated side, while turnover and DIO assess it from the speed side. See also our DIO calculator.
What does a GMROI below 1 mean?
A GMROI below 1.0× means the gross margin generated is smaller than the average inventory cost: each Rp1 tied up in inventory generates less than Rp1 of gross margin in the measured period. Example: a GMROI of 0.5 means each Rp1 of average inventory cost generates Rp0.5 of gross margin. This is descriptive — its meaning needs comparing against other products, previous periods, or category characteristics.
How can GMROI be increased in general?
Mathematically, since GMROI = gross margin (%) × inventory turnover, the figure rises when the gross margin percent grows or inventory turns faster — or a combination of both. That is an arithmetic relationship, not a recommended action: any operational step (pricing, product mix, purchasing, promotions) needs analysis with complete business data and its own risks, beyond this calculator’s scope.
When can GMROI not be calculated?
Two conditions make GMROI meaningless. First, zero average inventory cost — GMROI is undefined because the denominator is zero (this calculator shows an error message, not a number). Second, COGS exceeding sales so gross margin is negative: e.g. sales of Rp500,000, COGS of Rp600,000, and average inventory of Rp200,000 give gross margin of −Rp100,000 and GMROI of −0.5×, signaling a gross loss, not inventory productivity. This calculator’s results are educational estimates, not investment or financial advice.