How it works
GMROI, short for gross margin return on inventory investment, answers a simple question: for every dollar you have sitting in inventory, how many dollars of gross profit does it bring in over a year?
Example. A category earned $54,000 in gross profit over the year. The average inventory you carried for it was worth $30,000 at cost.
GMROI is 1.80. Every dollar tied up in that inventory earned $1.80 in gross profit.
What the number means
- Above 1.0: over a year, the inventory brings in more gross profit than the inventory itself is worth. The higher, the better.
- Below 1.0: the inventory brings in less gross profit than its own value over a year. That's a sign to cut back the stock, raise the margin or rethink the item.
Because it combines margin and speed, GMROI can show you things a margin alone can't. A low-margin item that sells constantly can earn more per dollar of shelf stock than a high-margin item that barely moves.
Where it helps
GMROI is most useful for comparing categories or items against each other when you're deciding where to put shelf space and cash. It's also a good argument in a conversation with a supplier: an item can have a great margin and still be a poor use of your money if it sits.
Common questions
- How do I get average inventory?
- The simplest version is your inventory at cost at the start of the year plus the end of the year, divided by two. If you count monthly, averaging all the counts is more accurate.
- How is this related to inventory turnover?
- GMROI is your gross margin multiplied by how many times over your sales cover your inventory, so selling faster or earning a better margin both raise it. The inventory turnover calculator shows the speed side on its own.
Last updated October 11, 2026.