Tools/Inventory Turnover Calculator

Reseller Inventory Turnover Calculator

Calculate how quickly your resale inventory is turning into cash — using COGS, average inventory value, and your chosen period.

Your inventory numbers
The purchase cost of items sold — not gross sales.
Total cost basis of unsold inventory at the start of the period.
Total cost basis of unsold inventory at the end of the period.
Use 30 for monthly checks, 90 for quarterly, or 365 for yearly.
Results
Inventory turnover ratio
Average inventory value
Days inventory outstanding
Annualised turnover
Unsold cash at period end
Track turnover by item in stokd

stokd connects every item, cost, sale, marketplace fee, source, and listing age so you can see which categories turn cash fastest — free for your first 25 items.

Formula
Inventory turnover for resellers

Inventory turnover = COGS ÷ average inventory value. For resellers, COGS means the cost basis of items that sold during the period. Average inventory value is beginning stock cost plus ending stock cost, divided by two.

This is different from a sell-through rate. A sell-through rate tells you what percentage of units moved. Turnover tells you whether your cash is cycling back into the business or sitting in unsold inventory.

Example
A monthly turnover check
01
Enter sold COGS
If you sold items that originally cost $600 during the month, enter $600 — even if gross sales were much higher.
02
Average your inventory
If you started with $2,400 in stock and ended with $2,000, average inventory is $2,200.
03
Read the velocity
$600 ÷ $2,200 = 0.27x monthly turnover. That means your current stock velocity is roughly one full turn every 110 days.
How to use it
Turn the number into sourcing decisions

Check turnover by platform, source, and category. eBay electronics, Poshmark clothing, Whatnot lots, and sneaker pairs can all have different healthy velocity ranges.

If turnover is falling while ending inventory value is rising, you are probably sourcing faster than you sell. Pair this calculator with the reseller inventory aging tracker and sell-through rate guide to find the specific stale items slowing the business down.

FAQ
Inventory turnover questions for resellers
How often should I calculate inventory turnover?

Monthly is enough for most small resellers. A weekly check can be noisy unless you list and sell high volume. Use a consistent period so you can compare the trend over time.

Should I use sale price or cost basis?

Use cost basis for inventory turnover. Gross sale price belongs in profit margin and ROI calculations. Turnover is about how quickly inventory cost cycles back into cash.

What if I sell one-of-one thrifted items?

You can still use turnover. Instead of tracking a single SKU, group items by category, source, platform, or age band. The goal is to see where cash moves fastest and where it gets stuck.

How does stokd help after the calculator?

stokd stores each item's purchase cost, source, platform, sale, fees, shipping, profit, and listing age. That makes turnover, stale stock, and category performance easier to monitor without rebuilding formulas in a spreadsheet.

Related reseller tools
ROI
Reseller ROI Calculator
Bulk Lots
Lot Splitter Calculator
Profit
Resale Profit Calculator
Stale Stock
Inventory Aging Tracker Guide