GMROI Calculator: Gross Margin Return on Inventory for Distributors
GMROI measures how many dollars of gross margin each dollar of inventory earns. It combines margin and turns in one number and is a better ranking tool than either alone.
Your numbers
Use an average of several month-end values, not a single snapshot.
Your results
Use consistent periods. Do not mix annual sales with a single-month inventory balance.
GMROI by average inventory
Sweeps Average inventory at cost from 1000000 to 8000000, holding your other inputs fixed.
GMROI by vendor line
Optional: we can show how GMROI could be ranked across vendor lines from your ERP data.
Optional. The tool and every export work without this. No spam.
How to use it
Enter annual net sales, your gross margin percent and average inventory at cost for the same group: a branch, a vendor line or a product category. Run it for several groups and compare. A line with a high margin but slow turns can earn less per inventory dollar than a thin-margin fast mover, and GMROI shows that directly.
- Use average inventory, not year-end, to avoid seasonal distortion.
- Compare within a product family, since norms differ by industry.
- Look at the chart to see how excess stock dilutes the return.
The formulas
GMROI equals gross margin dollars divided by average inventory at cost. Turns equal cost of goods sold divided by average inventory. Days on hand equal 365 divided by turns. With 25 million in sales at 24 percent margin, margin is 6 million and COGS is 19 million. On 4.5 million in average inventory, turns are about 4.2, days on hand are about 86, and GMROI is about 1.33.
Reading the result
A GMROI above 1.0 means the margin exceeds the cost of the inventory carried, but most distributors need more to cover operating cost and capital. Compare to your carrying cost rate: if GMROI is below your cost of carrying inventory plus allocated operating expense, the group is not paying its way.
Common mistakes
Using sales instead of cost of goods sold in the turn calculation overstates turns. Another is measuring inventory at selling price, which breaks the ratio. Finally, comparing GMROI across very different businesses, such as bulk commodities and electronic components, is rarely meaningful.
Frequently Asked Questions
What is a good GMROI?
It depends on your industry and operating cost. Many distributors aim for a GMROI of 2 or more at the line level. Compare against your own carrying cost and expenses rather than a published average.
How is GMROI different from turns?
Turns only measure speed. GMROI also includes margin, so it shows whether the stock that moves is actually profitable.
Which inventory value should I use?
Use average inventory at cost across the period, ideally the mean of month-end balances. Use the same cost basis as your COGS.
Can I run it for one item?
Yes, though the result can be noisy for slow movers. It is more reliable at product group, vendor or branch level.
Netray can help calculate GMROI by branch, vendor and product line directly from ERP sales and inventory history.
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