Inventory turnover: what it tells a corner store

Inventory turnover sounds like a term for big-box accountants, but it answers a simple question for a corner store: how fast does your stock sell? Turnover is how many times you sell through your average inventory in a period, usually a year. Higher turnover generally means products move quickly and cash isn't stuck on shelves. Low turnover can point to overbuying or slow sellers.

You don't need an accounting degree to use it. You need two numbers and a calculator.

How do you calculate inventory turnover?

The common formula is:

Inventory turnover = cost of goods sold ÷ average inventory value.

Cost of goods sold, or COGS, is what you paid for the products you sold during the period. Not the sale price, the cost.

Average inventory is the value of your inventory, at cost, averaged over the period. A simple way is to add your starting and ending inventory values and divide by two.

Wikipedia's page on inventory turnover explains other versions of the formula, but this one works well for a small store.

A worked example

Here's a hypothetical store.

Over the past year, the store's cost of goods sold was $240,000.

At the start of the year, inventory at cost was worth $18,000. At the end, it was $22,000.

Average inventory = ($18,000 + $22,000) ÷ 2 = $20,000.

Inventory turnover = $240,000 ÷ $20,000 = 12.

That means the store sold through its average inventory 12 times in the year, roughly once a month.

Another way to see it: divide the days in a year by turnover. 365 ÷ 12 ≈ 30. On average, an item sits about 30 days before it sells.

What do high and low turnover mean?

High turnover usually means products sell quickly. Cash comes back fast, and there's less risk of items expiring or going stale. Convenience stores selling drinks, snacks, and daily items often have fairly high turnover.

But very high turnover can also mean you're running too lean. If you're often out of stock, you're losing sales even though turnover looks good.

Low turnover means products sit longer. That can mean you're overbuying, carrying slow sellers, or holding too much of certain categories. Cash is tied up on shelves and in the back room.

There's no single right number. It depends on what you sell. A store that sells mostly beverages and snacks will turn inventory faster than one that sells phone accessories and general merchandise. Compare your store with itself over time.

Why look at turnover by category?

Store-wide turnover hides a lot. The real insights come from breaking it down.

Here's a hypothetical. Your store's overall turnover is 12. But when you break it down:

Beverages turn over 24 times a year.

Snacks turn over 18 times.

Health and beauty items turn over 4 times.

Phone accessories turn over 3 times.

That tells you where cash is tied up. Beverages and snacks move fast. Health and beauty and accessories move slowly. Maybe you're carrying too many varieties of slow items, or too much stock of each.

If your POS tracks sales by category and you know your inventory costs by category, you can run these numbers. If you use NRS POS, learn what reporting it offers at NRS POS.

How do you improve turnover?

A few practical steps.

Order based on sales data, not guesses. Your POS shows what actually sells.

Cut or reduce slow sellers. If an item hasn't sold in months, it's taking space from something that would.

Order smaller amounts more often for items with steady demand, if your supplier allows it.

Watch new products. Order a small amount first and reorder once they prove themselves.

Clear out dead stock with markdowns or bundles, so the cash comes back.

For general guidance on inventory planning, Wikipedia's page on inventory management is a readable overview. When restocking store supplies, the store supplies category on NRS Marketplace covers bags and counter items.