# GMROI Calculator – Gross Margin Return on Investment

URL: https://speedycalculator.com/calculators/finance/gmroi/
Last updated: 2026-10-25

> The GMROI calculator works out how many dollars of gross margin your inventory earns for each dollar invested in it, from gross profit and average inventory cost.

## Inputs

- Starting inventory cost
- Final inventory cost
- Gross profit

## Results

- Average inventory cost
- GMROI
- GMROI as a percentage

## Formula

```
Average inventory cost = (beginning + ending inventory at cost) ÷ 2
GMROI = gross profit ÷ average inventory cost
```

## Explanation

GMROI is a key retail metric. A GMROI above 1 means you sell inventory for more than it costs; many retailers aim for 3 or more. It helps decide which products deserve shelf space and which tie up cash.

### How to use the GMROI Calculator – Gross Margin Return on Investment

- **Starting inventory cost**
- **Final inventory cost**
- **Gross profit**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the inventory cost at the start and end of the period and the gross profit earned on it.

### Tips

- Use figures for the same period (a month, a quarter or a year) for every input so ratios compare like with like.
- Track the metric over time – the trend usually tells you more than a single value.
- Compare your result with industry benchmarks, which vary a lot between sectors.
- Treat the result as a starting point for a decision, then check the assumptions behind each input.

### Common mistakes to avoid

- Mixing monthly and yearly numbers in the same calculation.
- Using revenue where the formula needs profit (or the other way round).
- Forgetting hidden costs such as taxes, fees, overheads or your own time.

### Inputs explained

FieldWhat to enterStarting inventory costAmount in your currencyFinal inventory costAmount in your currencyGross profitAmount in your currency

### What each result means

- **Average inventory cost** = ([Starting inventory cost] + [Final inventory cost])÷2
- **GMROI** = [Gross profit]÷[Average inventory cost]
- **GMROI as a percentage** = [GMROI]×100

### Example values

How the main result changes when **Starting inventory cost** changes and everything else stays at the example values above:

Starting inventory costGMROI (×)20,0003.8630,0003.3840,000350,0002.760,0002.4580,0002.08

## Worked example

Inputs — Starting inventory cost: $40,000; Final inventory cost: $50,000; Gross profit: $135,000.

Results — Average inventory cost = $45,000.00; **GMROI = 3 ×**; GMROI as a percentage = 300 %.

## FAQ

**What is a good GMROI?**
Above 1 means profit; 3 or more is a common retail target.

**How do I improve GMROI?**
Raise margins, reduce slow-moving stock and turn inventory faster.

**Is GMROI the same as inventory turnover?**
No – GMROI includes margin, turnover only counts how often stock is sold.

**What formula does the GMROI Calculator – Gross Margin Return on Investment use?**
Average inventory cost = (beginning + ending inventory at cost) ÷ 2.