Inventory Turnover Ratio

What is the inventory turnover ratio?

The inventory turnover ratio measures how many times a business sells and replaces its stock over a period, calculated as cost of goods sold divided by average inventory. A ratio of 8 means the business cleared and refilled its shelves eight times in the year. The higher the number, the faster stock is moving; the lower it is, the longer goods sit before they sell.

It matters because inventory is cash sitting on a shelf. Every unit you hold has been paid for but not yet earned back, so how fast it turns tells you how efficiently that cash is working. A healthy turnover ratio means you are not overstocked, not tying up money in goods that may never sell, and not paying to store things customers do not want.

The inventory turnover ratio formula

The inventory turnover ratio formula is cost of goods sold divided by average inventory, where average inventory is the opening balance plus the closing balance, divided by two. Using cost of goods sold rather than revenue keeps both the top and bottom of the fraction at cost, so the ratio is not inflated by your profit margin. Enter your figures below to see your turnover ratio and how many days, on average, stock sits before it sells.

Worked through: a business with cost of goods sold of 600,000, opening inventory of 70,000 and closing inventory of 80,000 has average inventory of 75,000. Turnover is 600,000 divided by 75,000, which is 8.0. That means stock turns over eight times a year, or roughly every 46 days (365 divided by 8). Cut the average inventory you carry and the ratio rises; let stock build up and it falls.

What is a good inventory turnover ratio?

There is no universal good number: a healthy inventory turnover ratio depends entirely on the industry, but most businesses sit somewhere between 4 and 8 times a year. Comparing your ratio to a business in a different sector tells you almost nothing; comparing it to your own past and to direct competitors tells you a lot. The rough ranges below show how widely normal varies.

Watch the direction and the balance

What matters most is the trend and the balance. A ratio that is rising over time usually signals tightening stock control or stronger demand, so treat a falling ratio as a prompt to investigate slow-moving lines. A very high ratio is not automatically good either: if it climbs because you are constantly running out of stock, you are losing sales and frustrating customers, so a spiking ratio is a prompt to check you are not under-stocking. The sweet spot is fast enough to keep cash free and storage costs down, but slow enough that you can always fill an order.

Read it at the product level

It also helps to read the ratio per product, not just the whole business. A single company-wide number averages your fastest and slowest lines together, which can hide a real problem. A homewares retailer might post a respectable overall turnover of 6 while a third of its catalogue quietly turns less than once a year, tying up cash and shelf space. Breaking the ratio down by category or SKU is where it stops being a reporting figure and starts driving decisions: which lines to reorder, which to discount, and which to drop.

Inventory turnover and days inventory outstanding

Days inventory outstanding is the turnover ratio expressed in days: divide 365 by the turnover ratio to see how long, on average, a unit sits in stock before it sells. A turnover of 8 becomes about 46 days; a turnover of 4 becomes about 91 days. Many people find the days version easier to act on, because "stock sits for 46 days" is more concrete than "turnover is 8". The two say exactly the same thing from opposite ends.

Days inventory outstanding is also one of the three legs of the cash conversion cycle, alongside how long customers take to pay and how long you take to pay suppliers. That is the bridge from inventory to accounts receivable. Inventory turnover tells you how fast goods become sales; your receivables metrics tell you how fast those sales become cash. Improving one without the other only moves the bottleneck. A faster turnover frees cash from the shelf, but if that cash then sits in unpaid invoices, the working-capital gain never reaches your bank account.

How to improve your inventory turnover ratio

You raise the inventory turnover ratio by either selling faster or carrying less stock, and the cleanest gains come from carrying less of the wrong stock. The levers fall into two groups, and they reinforce each other.

Using a defensible reorder size such as the economic order quantity stops the over-ordering that quietly drags the ratio down, and small, steady improvements compound, because every day shaved off how long stock sits is a day's worth of cash handed back to the business.

The caution is not to chase the ratio for its own sake. Slashing stock to flatter the number can leave you unable to meet demand, and the lost sales cost far more than the storage you saved. The goal is efficient stock, not minimal stock. Read the turnover ratio next to your service levels and your accounts receivable reporting, so you can see whether faster-moving inventory is genuinely turning into collected cash rather than just shifting the pressure onto your receivables. Inventory and receivables are the two big places working capital hides, and the strongest businesses keep both lean at once.