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Pricing math

GMROI Calculator

How many gross margin dollars every dollar tied up in inventory earns per year, retail’s favorite buying yardstick.

GMROI = annual gross margin dollars ÷ average inventory cost. A store earning $150,000 of gross margin a year on an average inventory investment of $60,000 has a GMROI of 2.5: every dollar sitting in stock returns $2.50 of gross margin annually. GMROI matters because margin alone hides slow movers: a 60% margin product that sits for a year can earn less per invested dollar than a 30% margin product that turns eight times. Enter your annual gross margin and average inventory at cost to get the number.

GMROI Calculator — your numbers

GMROI

2.50

Margin per inventory dollar

$2.50

Estimate only. Results reflect exactly the numbers you enter — verify against your own accounting before making pricing decisions.

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Worked examples

Healthy specialty retailer

Annual gross margin $150,000.00
Average inventory $60,000.00
GMROI 2.50
Margin per inventory dollar $2.50

A GMROI of 2.5, comfortably above the ~2.0 line most retailers target.

Overstocked store

Annual gross margin $80,000.00
Average inventory $65,000.00
GMROI 1.23
Margin per inventory dollar $1.23

Barely $1.23 back per inventory dollar: capital is trapped on the shelf.

The GMROI formula. GMROI stands for gross margin return on inventory investment, and the formula is GMROI = annual gross margin dollars ÷ average inventory cost. It reads as a multiple: 2.5 means every dollar tied up in stock returned $2.50 of gross margin over the year. Two conventions matter. Use gross margin in dollars, not a percentage, and use average inventory at cost across the period rather than a single month-end snapshot, because one seasonal peak will distort the result badly in either direction.
Worked examples. The middle two rows are the instructive pair — identical GMROI of 1.5 reached from opposite directions, one by holding too much stock and one by earning too little margin on the right amount of stock.
Gross marginAvg inventoryGMROI
$150,000$60,0002.5×
$150,000$100,0001.5×
$90,000$60,0001.5×
$240,000$80,0003.0×
Why the diagnosis differs even when the score is identical. Because GMROI multiplies margin against stock level, an identical result can have opposite fixes: the $150,000-on-$100,000 row needs inventory cut, while the $90,000-on-$60,000 row needs price or cost work instead. Reading GMROI alongside inventory turnover separates the two — turnover moves when stock levels change and stays put when only margin does, so the pair tells you which lever the score is actually reacting to.

Frequently asked questions

What is a good GMROI?

A GMROI above 1.0 means inventory returns more margin than it costs to hold in stock, but 1.0 barely covers carrying costs. Most healthy retailers target 2.0–3.0 overall; fast-turning categories like consumables can exceed 4.0, while slow luxury goods may run lower and compensate with margin. Compare products against your own portfolio average: the gap between your best and worst GMROI is where the buying budget should move.

How do I calculate average inventory at cost?

Take your inventory value at cost (not retail) at regular intervals and average them: (beginning + ending) ÷ 2 works for a rough annual figure, but a monthly average of 12–13 snapshots is far more honest for seasonal businesses. Using a single year-end count understates average inventory for anyone who stocks up before peak season, which inflates GMROI.

Why use GMROI instead of just margin percentage?

Margin ignores time and capital. A 60% margin item that turns once a year earns 0.6 GMROI-style dollars per invested dollar; a 30% margin item turning six times earns roughly 1.8. GMROI multiplies margin by velocity, so it ranks products by what they actually pay you per dollar tied up, which is the real constraint for a cash-limited store.

How do I improve a weak GMROI?

Attack either side of the fraction. Raise margin dollars: increase prices where demand allows, cut landed costs, drop chronic markdown items. Or shrink the inventory base: order smaller quantities more often, clear dead stock even at a loss (it frees denominator dollars), and reallocate open-to-buy toward the products this calculator scores highest.

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Part of the Pricing & Margins collection.