Inventory Turnover Ratio: The Formula, a Worked Example, and What "Good" Looks Like

Your inventory turnover ratio tells you how many times you sold and replaced your stock over a period. It's one of the few numbers that exposes dead stock, overbuying, and cash stuck on shelves, and most operators either never calculate it or read it wrong.

Here is the formula, a worked example you can copy, what a healthy number looks like in your industry, and the concrete moves that actually push it in the right direction.

What the inventory turnover ratio actually tells you

Turnover measures velocity. A ratio of 6 means you cycled through your entire average stock six times in the period. A ratio of 2 means you turned it twice, so on average product sat around for roughly half the year before selling.

Higher usually means healthier. You're converting inventory into sales quickly, holding less cash in stock, and paying less for storage, insurance, and obsolescence. But higher isn't automatically better. Push turnover too high and you start stocking out, disappointing customers, and paying for rushed reorders. The goal is the right number for your product, not the biggest one you can hit.

The inventory turnover ratio formula

Here it is:

Inventory turnover ratio = Cost of goods sold / Average inventory

Two inputs, and the second one trips people up:

• Cost of goods sold (COGS). What the goods you sold actually cost you over the period. Pull it from your income statement. Use COGS, not revenue. Revenue includes your margin, which inflates the ratio and makes you look faster than you are.
• Average inventory. The average value of stock you held during the period, at cost. The simplest version is (beginning inventory + ending inventory) / 2. If your business is seasonal, average more points (monthly closing values divided by 12) so one quiet January doesn't skew the whole year.

A common mistake is dividing sales revenue by inventory. That gives you a number, but not the turnover ratio. It's apples to a different fruit, because the top is priced with margin and the bottom is priced at cost.

A worked example

Say you run a shop selling coffee gear.

• Your COGS for the year was $480,000.
• You started the year with $95,000 in inventory (at cost).
• You ended with $65,000.

First, average inventory:

Average inventory = (95,000 + 65,000) / 2 = 80,000

Then turnover:

Inventory turnover ratio = 480,000 / 80,000 = 6

So you turned your stock 6 times. To make that human, convert it to days:

Days inventory outstanding = 365 / 6 = ~61 days

On average, a product sat on your shelf about 61 days before it sold. Now you have something you can act on. Is 61 days fine for espresso machines and terrible for whole beans that go stale? Almost certainly. Which is why the single blended number is only the starting point (more on that below).

What counts as a good inventory turnover ratio?

There's no universal target. A grocer and a jeweler live in different worlds, and both can be run well. Rough industry ballparks:

Industry	Typical turnover
Grocery / perishable food	12 to 20+
Fast fashion / apparel	4 to 8
Consumer electronics	6 to 10
Auto parts	3 to 6
Furniture	2 to 4
Jewelry / luxury	1 to 3

Use these as sanity checks, not goals. The two comparisons that matter more than any benchmark:

1. Your ratio against your own history. Is turnover trending up or down quarter over quarter? A falling number is an early warning that stock is piling up.
2. Your ratio per product and per location. A single company-wide figure hides everything. Your fast movers might turn 15 times while a shelf of dead stock turns 0.5, and the blended average makes both look like an unremarkable 6.

Turnover ratio vs days inventory outstanding

These two describe the same thing from opposite ends, so pick whichever your team reads faster.

• Inventory turnover ratio answers "how many times did we sell through our stock?" Higher is faster.
• Days inventory outstanding (DIO) answers "how many days does a unit sit before it sells?" Lower is faster.

Convert between them with DIO = 365 / turnover ratio. Turnover is the cleaner number for a board slide. DIO is more intuitive on the warehouse floor, because "this SKU sits for 90 days" lands harder than "this SKU turns 4 times."

How to improve a turnover ratio that's dragging

If your number is low and cash is tight, work these in order. The early ones cost nothing.

1. Find your slow movers. Rank every SKU by its own turnover. The bottom 10% is where your cash is trapped. You cannot fix an average, only the items dragging it down.
2. Clear the dead stock. Discount it, bundle it, or return it to the supplier. A one-time markdown hurts less than storing unsellable product for another year.
3. Buy tighter and more often. Large infrequent orders crush turnover and inflate holding costs. Smaller, more frequent purchase orders keep average inventory down. This is where a solid reorder point per product earns its keep.
4. Fix your forecasting inputs. Turnover craters when you buy on gut feel. Base reorder quantities on real usage rates, not last year's guess.
5. Kill or flag the true zeros. Any SKU that hasn't moved in two turnover periods is a decision waiting to happen: discontinue it, or understand exactly why you're holding it.
6. Track it per location. Stock that's dead in one warehouse may be selling out in another. Redistribute before you reorder.

The hard part isn't the arithmetic. It's having per-SKU, per-location COGS and inventory values on hand without exporting three spreadsheets and reconciling them by Friday.

Where Inventoros fits

Inventoros tracks stock at cost across every location, so per-product and per-location turnover comes from the same data you already keep, no export-and-reconcile ritual. It's free, open source, and self-hosted, which means the numbers (and the customer data behind them) stay on your own server. If you'd rather query turnover programmatically or wire it into a dashboard, the REST and GraphQL API exposes stock and movement data directly, and the docs walk through install on cPanel, a VPS, or Docker.

FAQ

Is a higher inventory turnover ratio always better? No. Higher turnover means less cash tied up and fewer holding costs, but past a point it signals you're understocking. If turnover climbs while stockouts and rush-order fees also climb, you've gone too far. Balance velocity against your service level and reorder costs.

Should I use COGS or sales in the formula? COGS. Both the top and bottom of the ratio should be valued at cost so they're comparable. Using sales revenue on top mixes in your margin and overstates turnover. The only time people use sales is a rough retail-price approximation, and it's less accurate.

How often should I calculate inventory turnover? Annually for the headline figure, but review it monthly or quarterly at the SKU level. Trends matter more than any single snapshot, and a monthly cadence catches slow movers while there's still time to act before they become dead stock.

What's the difference between inventory turnover and the reorder point? Turnover is a backward-looking health metric: how fast you sold through stock. The reorder point is a forward-looking trigger: the level at which you place your next order. You use turnover to spot what's overstocked or dead, and reorder points to keep the healthy items in stock without overbuying.