Calculator Inputs
Use the fields below to evaluate inventory movement, margin performance, weeks of cover, and reorder needs for a single ecommerce product.
Formula Used
Sell-through rate measures how much inventory sold during a period relative to a chosen stock basis.
Available for Sale = Beginning Inventory + Units ReceivedSell-Through Rate (%) = (Units Sold ÷ Selected Basis) × 100Revenue = Units Sold × Unit Selling PriceGross Profit = Revenue - Cost of Goods SoldInventory Turnover = Cost of Goods Sold ÷ Average Inventory ValueWeeks of Cover = Ending Inventory ÷ Average Weekly SalesReorder Quantity = (Weekly Sales × Lead Time) + Safety Stock - Ending Inventory
Many ecommerce teams use Units Sold ÷ Units Received for campaign or seasonal analysis, while others use Units Sold ÷ Available for Sale for a broader inventory view.
How to Use This Calculator
- Enter beginning inventory, newly received units, and total units sold during the selected time period.
- Choose whether ending inventory should be auto-calculated or manually entered from your stock records.
- Select the sell-through basis that matches your reporting method.
- Add selling price, unit cost, lead time, safety stock, and your target sell-through percentage.
- Click Calculate Sell-Through to display results above the form.
- Review the metrics, chart, and recommendations, then export your report in CSV or PDF format.
Example Data Table
| Product | Beginning Inventory | Units Received | Units Sold | Ending Inventory | Sell-Through Rate |
|---|---|---|---|---|---|
| Running Shoes | 300 | 450 | 540 | 210 | 72.00% |
| Wireless Earbuds | 180 | 260 | 300 | 140 | 68.18% |
| Organic Skincare Set | 120 | 160 | 190 | 90 | 67.86% |
| Travel Backpack | 90 | 150 | 170 | 70 | 70.83% |
FAQs
1) What is a good sell-through rate in ecommerce?
A good rate depends on category, season, and pricing strategy. Many sellers aim for 60% to 80% over a planned period. Fast-moving essentials may exceed that, while luxury or seasonal goods can perform well at lower levels.
2) Why does denominator choice matter?
Using units received focuses on recent replenishment performance. Using available-for-sale gives a wider stock view. Beginning inventory is helpful for opening stock analysis. The right basis depends on your reporting goal and planning method.
3) Can high sell-through still be risky?
Yes. A very high rate may signal great demand, but it can also mean underbuying and missed revenue from stockouts. Pair sell-through with weeks of cover and reorder timing for better decisions.
4) How often should I review sell-through?
Weekly reviews work well for fast-moving ecommerce products. Slower categories may only need biweekly or monthly checks. During promotions, launches, or seasonal peaks, daily tracking can be useful.
5) Does this calculator account for profitability?
Yes. It estimates revenue, cost of goods sold, gross profit, and gross margin. That helps you see whether fast stock movement also supports healthy financial performance.
6) What is weeks of cover?
Weeks of cover estimates how long current ending inventory can support ongoing demand. It divides remaining units by average weekly sales. Lower values often indicate faster reorder urgency.
7) Why include safety stock and lead time?
Lead time shows how long replenishment takes. Safety stock protects against delays or demand spikes. Together, they make reorder recommendations more practical than using sell-through alone.
8) Can I use this for marketplaces and direct store sales together?
Yes. Combine units sold across channels if they draw from the same inventory pool. If channels use separate stock allocations, calculate each one separately for clearer insights.