Days in Inventory Calculator

Updated on 28-Apr-2025

Easily calculate inventory turnover and days in inventory with our free Days in Inventory Calculator. Improve stock management and financial planning in seconds.

$
$
Days
Typically 365 for annual analysis
Results
Days
x per period
Retail: 30-60 days | Manufacturing: 60-90 days | Perishables: 1-10 days

Efficient inventory management is essential for maintaining healthy cash flow and operational performance. The Days in Inventory Calculator helps you determine how long your inventory stays in storage before it is sold — a critical metric for businesses to monitor.

This tool calculates:

  • Days in Inventory
  • Inventory Turnover

What is Days in Inventory?

Days in Inventory, also known as Days Sales of Inventory (DSI), shows the average number of days it takes a company to sell its inventory during a specific period.

A lower number means faster inventory movement, which is generally a sign of efficiency.

Inputs Required

To use this calculator, you'll need:

  • Average Inventory ($) – Average inventory over the period.
  • Cost of Goods Sold (COGS) ($) – Total cost of products sold during the period.
  • Time Period (Days) – The length of the time period (usually 30, 90, or 365 days).

Outputs

  • Inventory Turnover – How many times inventory was sold and replaced during the period.
  • Days in Inventory – Average number of days inventory remained before being sold.

Formula to Calculate Inventory Turnover

Inventory Turnover=COGSAverage Inventory\text{Inventory Turnover} = \frac{\text{COGS}}{\text{Average Inventory}}

Formula to Calculate Days in Inventory

Days in Inventory=Time Period (in Days)Inventory Turnover\text{Days in Inventory} = \frac{\text{Time Period (in Days)}}{\text{Inventory Turnover}}

Example Calculation

Let’s calculate Days in Inventory using the following inputs:

  • Average Inventory = $25,000
  • COGS = $100,000
  • Time Period = 365 days

Step 1: Inventory Turnover

Inventory Turnover=100,00025,000=4\text{Inventory Turnover} = \frac{100{,}000}{25{,}000} = 4

Step 2: Days in Inventory

Days in Inventory=3654=91.25 days\text{Days in Inventory} = \frac{365}{4} = 91.25 \text{ days}

 

Final Answer:

  • Inventory Turnover: 4
  • Days in Inventory: 91.25 days

Why This Matters

Knowing your Days in Inventory helps you:

  • Improve inventory control
  • Reduce holding costs
  • Identify slow-moving products
  • Forecast cash flow more accurately

Use This Calculator For:

  • Retail and eCommerce businesses
  • Warehouse and logistics management
  • Financial analysis and reporting
Days in Inventory Calculator