Inventory Turnover Calculator 2026: Sell-Through Rate & Inventory Health Score
Calculate inventory turnover rate, sell-through percentage, and days of supply. Get an inventory health score with category benchmarks.
What this tool helps you do
Calculate inventory turnover rate, sell-through percentage, and days of supply. Get an inventory health score with category benchmarks. Identify slow movers and optimize stock levels.
Interactive inputs and calculations load after the app boots. Use this prerendered preview to understand what the tool covers before opening the live experience.
Best for
- inventory turnover calculator
- sell through rate
- inventory health score
- days of supply
- stock turnover
Frequently Asked Questions
How does the inventory turnover calculator work?
Enter your total cost of goods sold over a period and your average inventory value. The calculator divides COGS by average inventory to produce your turnover ratio, then converts it to days of supply. A secondary sell-through tab lets you enter units listed versus units sold to score your inventory health against category benchmarks for clothing, electronics, and collectibles.
What inventory turnover ratio is healthy for a reseller?
A healthy reseller inventory turnover ratio is 4 to 12 times per year, meaning your full stock cycles every 1 to 3 months. Clothing resellers targeting fast fashion should aim for 8 or higher; furniture and collectible flippers naturally run lower at 3 to 5. A ratio below 2 signals that dead stock is tying up capital — items that haven't sold in 60 days are candidates for repricing or liquidation.
What is sell-through rate and how is it different from inventory turnover?
Sell-through rate is the percentage of listed units that actually sold in a given period — units sold divided by units available. Inventory turnover is a dollar-value metric: cost of goods sold divided by average inventory. Both diagnose inventory health but from different angles. A 70% sell-through rate combined with a low dollar turnover ratio typically means you're moving cheap items fast but holding expensive slow movers.
How do I calculate days of supply for my reseller inventory?
Days of supply is your average inventory value divided by average daily cost of goods sold. If you hold $3,000 in inventory and sell $100 in cost of goods per day, your days of supply is 30. The goal is to keep days of supply tight — under 45 days for most categories — so capital isn't locked in unsold inventory. High days of supply often precede a cash-flow crunch when sourcing opportunities arise.
Which items should I flag as dead inventory and how quickly?
Flag items as dead inventory after 45 days without a sale for high-velocity categories like clothing and shoes, and after 90 days for slower categories like furniture and vintage collectibles. Once flagged, run a 10 to 20% price drop first, then cross-list to another platform if it still doesn't move. Holding dead inventory past 90 to 120 days costs you the sourcing capital that could be funding faster-turning flips.
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