Inventory Turnover Calculator

What Is Inventory Turnover?

Inventory turnover is the number of times a business sells through its average stock in a period. A turnover of 2.4 in a year means the company sold goods costing 2.4 times what it usually holds on its shelves. The higher the figure, the faster goods move from purchase to sale.

Turnover matters because inventory ties up cash, needs storage and can spoil, go out of fashion or be damaged. Fast turnover frees cash and lowers those risks; very slow turnover is often a sign of overstocking or goods that do not sell.

Inventory Turnover Formula

• COGS: cost of goods sold for the period, from the income statement.
• Beginning and ending inventory: inventory at cost on the balance sheet at the start and end of the period.
• Days in period: 365 for a year, 90 or 91 for a quarter, 30 for a month.

How to Calculate Inventory Turnover

A wholesaler has COGS of 1,200,000 for the year, inventory of 450,000 at the start and 550,000 at the end:

1. Find average inventory. (450,000 + 550,000) ÷ 2 = 500,000.
2. Divide COGS by it. 1,200,000 ÷ 500,000 = 2.4.
3. Find days in inventory. 365 ÷ 2.4 ≈ 152.08 days.

The wholesaler turns its inventory 2.4 times a year, so an item sits in stock for about 152 days on average before it is sold.

What 2.4 Turns Looks Like

The bar is drawn to scale. Each full block is one complete sale and replacement of the average stock.

Days in Inventory (DIO)

Days in inventory turns the ratio into time. It can also be worked out directly:

With the wholesaler figures, 500,000 ÷ 1,200,000 × 365 ≈ 152.08 days, the same answer. Some analysts use a 360-day year, which gives 150 days; use the same convention when you compare companies. Days in inventory is one part of the cash conversion cycle, together with days sales outstanding and days payables outstanding.

COGS or Sales?

Some sources divide sales, not COGS, by average inventory. Sales include the profit margin while inventory is held at cost, so this overstates turnover. If the wholesaler had sales of 1,800,000:

Use COGS for a like-for-like ratio, and only compare a sales-based figure with other sales-based figures.

Inventory Turnover Examples

A grocery store. COGS of 9,600,000 for the year, inventory of 380,000 at the start and 420,000 at the end:

Fresh food has to sell quickly, so groceries turn their stock many times a year.

One quarter of a shop. COGS of 300,000 over 90 days, inventory of 140,000 at the start and 160,000 at the end:

Two turns in a quarter is about 2 × 365 ÷ 90 ≈ 8.11 turns a year. The calculator shows this annual figure whenever the period is not 365 days.

A furniture maker. COGS of 600,000, inventory of 350,000 at the start and 450,000 at the end:

Large, made-to-order or slow-selling goods naturally turn more slowly.

What Raises or Lowers Turnover

Starting from the wholesaler (COGS 1,200,000, inventory 450,000 then 550,000, 365 days), each change below is made on its own:

Turnover rises when more is sold from the same stock or the same sales come from less stock.

High vs Low Inventory Turnover

There is no single good number. Grocery and fast fashion turn stock quickly, while furniture, jewellery, machinery and car dealers turn it slowly. Compare a business with its own past results and with similar companies, and watch the trend.

How to Improve Inventory Turnover

• Forecast demand better so orders match what actually sells.
• Clear slow stock with discounts, bundles or returns to suppliers.
• Order smaller amounts more often, where suppliers allow it.
• Trim the range to drop items that rarely sell.

Cutting stock too far can cause stock-outs, so check service levels as well as turnover.

What the Result Leaves Out

• Seasonality. A two-point average can miss a large peak in between; use monthly averages for seasonal businesses.
• Inventory method. FIFO, LIFO and weighted average give different COGS and inventory values, which changes the ratio.
• Product mix. One company-wide figure can hide fast and slow lines; work it out per product or category too.
• Write-downs. Writing off obsolete stock lowers inventory and can make turnover look better than sales justify.

The result is for education and planning and is not accounting, tax or investment advice.

Key Terms

Inventory turnover

COGS ÷ average inventory.

Average inventory

(Beginning + ending inventory) ÷ 2.

Days in inventory

Average days stock is held before sale.

COGS

Cost of the goods sold in the period.

Stock-out

Running out of an item customers want.

How to Use the Inventory Turnover Calculator

1. Enter COGS. Type the cost of goods sold for the period, such as 1,200,000.
2. Enter beginning inventory. Type the inventory at cost at the start of the period, such as 450,000.
3. Enter ending inventory. Type the inventory at cost at the end of the period, such as 550,000.
4. Enter the days in the period. Type 365 for a year, 90 for a quarter or 30 for a month.
5. Read and copy the result. Inventory turnover appears as you type, with the working, average inventory and days in inventory, plus an annual figure for shorter periods. Press Copy to copy it, or Clear or Esc to start again.

Example: COGS of 600,000 with inventory of 350,000 at the start and 450,000 at the end of a 365-day year gives a turnover of 1.5 and about 243.33 days in inventory.

Who Can Use This Calculator?

Frequently Asked Questions (FAQs)

Sources

• Corporate Finance Institute. Inventory Turnover.
• Corporate Finance Institute. Days Inventory Outstanding.
• Wall Street Prep. Inventory Turnover Ratio.
• WallStreetMojo. Inventory Turnover Ratio.
• Shopify. Inventory Turnover Ratio: Formula and How to Improve.
• Wikipedia. Inventory turnover.
• Wikipedia. Days in inventory.