Inventory Days Calculator

What is Days of Inventory (DOI)?

Days of Inventory (DOI), also known as Days Sales of Inventory (DSI) or Inventory Days on Hand (DOH), measures how many days your current inventory will last at your average daily sales rate. It helps you plan reorders, prevent stockouts, and optimize inventory levels for better cash flow.

Inventory Days Formulas

Why Inventory Days Matter

• Cash Flow Management: Lower inventory days means less capital tied up in stock
• Prevent Stockouts: Know when to reorder before running out
• Reduce Holding Costs: Minimize storage, insurance, and obsolescence expenses
• Optimize Operations: Balance service levels with inventory investment
• Benchmark Performance: Compare efficiency against industry standards

How to Reduce Inventory Days

• Improve Demand Forecasting: Use historical data and trends for accurate predictions
• Negotiate Shorter Lead Times: Work with suppliers for faster delivery
• Implement Just-In-Time: Order closer to when inventory is needed
• ABC Analysis: Focus on high-value, fast-moving items
• Clear Slow Movers: Run promotions on stagnant inventory
• Review Safety Stock: Optimize buffer levels based on actual risk