Inventory Turnover Calculator 2026: COGS, Sell-Through, and Sourcing Decision
Calculate reseller inventory turnover from COGS and average inventory, then check days of supply, sell-through, stale stock, storage drag, and sourcing decision.
What this tool helps you do
Use COGS, average inventory, unit movement, stale stock, revenue, and storage cost to decide whether to keep sourcing, reprice, or clear inventory.
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
- reseller inventory turnover
- sell through rate calculator
- days of supply calculator
- dead inventory calculator
Inventory turnover workflow for resellers
The calculator uses the accounting formula inventory turnover = COGS divided by average inventory. For resellers, the practical decision is whether cash is turning quickly enough to keep sourcing or whether stale stock needs repricing, bundling, liquidation, or a sourcing freeze.
Editable category targets are planning thresholds only. They are not official benchmarks. The stable math is COGS, average inventory cost, days of supply, unit sell-through, stale-unit share, and storage drag.
- Inputs: beginning inventory cost, purchases, ending inventory cost, units at start, units added, units sold, ending units, stale units, revenue, storage cost, period length, and editable targets.
- Output decision: keep sourcing, reprice and restrict sourcing, or freeze sourcing and clear stock.
- Risk prevented: using revenue alone while ending inventory cost and stale units keep climbing.
Turnover inputs
| Input | Where it comes from | Why it matters |
|---|---|---|
| COGS | Beginning inventory plus purchases minus ending inventory | Shows cost value actually moved through sales. |
| Average inventory | Beginning plus ending inventory divided by two | Measures capital tied up during the period. |
| Sell-through | Units sold divided by units available | Catches unit velocity even when dollar turnover looks acceptable. |
| Stale units | Ending inventory older than your markdown rule | Shows cash trapped in old listings. |
Formula sources checked August 8, 2026
Inventory turnover formula
Reference for COGS divided by average inventory and interpretation limits.
Amazon inventory dashboard context
Official Seller Central context for inventory performance as an efficiency metric.
Amazon inventory health context
Official Seller Central context for inventory health and sell-through recommendations.
Frequently Asked Questions
How is inventory turnover calculated?
Inventory turnover is COGS divided by average inventory. In this tool, COGS equals beginning inventory cost plus purchases minus ending inventory cost, and average inventory is the average of beginning and ending inventory cost.
What is days of supply?
Days of supply estimates how many days of inventory remain at the current cost-of-goods velocity. It uses ending inventory cost divided by average daily COGS.
Are the category targets official benchmarks?
No. The category presets are editable planning thresholds to help decide when to reprice or pause sourcing. The official-style formula is turnover from COGS and average inventory.
When should I freeze sourcing?
Freeze or sharply limit sourcing when COGS is not moving, days of supply is far above your target, stale units are rising, or storage cost is consuming a meaningful share of inventory value.
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Guides related to this tool
Inventory Turnover for Resellers: 2026 Cash Flow System
Calculate sell-through, aging buckets, reorder rules, and cash-recycle examples so stale inventory turns back into buying power.
Inventory Management for Resellers: SKUs, Storage & Systems
The broad inventory-systems pillar: spreadsheets, SKUs, storage, reseller apps, and accounting workflows for resellers who need control before chaos gets expensive.
Just-in-Time Inventory 2026: Cut Capital Risk
A practical JIT inventory model for resellers in 2026. Learn how to reduce capital tied up in stock, preserve sell-through, and run lean sourcing cycles with clear replenishment triggers.