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Beginning inventory + units received: everything you could have sold in the period. Decision: whether the deliveries you added belong in the base, or in the next period.
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Sell-through rate calculator
Enter the units you started a period with, the units you received and the units you sold. This calculator gives your sell-through rate, the units left and how many weeks they last at your current sales rate.
Your results
You sold 60% of the 400 units you had. At 60 units a week, the 160 units left last 2.7 weeks.
- Sell-through rate
- 60%
- Units sold ÷ units available
- Weeks of cover
- 2.7 weeks
- Units remaining ÷ units sold per week
- Units remaining
- 160
- Units available − units sold
- Units sold per week
- 60
- Units sold ÷ days in period × 7
- Units available (beginning + received)
- 400
Units available are the beginning inventory plus the units received. Use one product, one category or one delivery, and the same period for every number.
The start values are illustrative data.
How it works
Every step behind the numbers, worked through for the start values.
Illustrative data. An example product started a 28-day period with 300 units and received 100 more. It sold 240 units.
| Step | Calculation | Result |
|---|---|---|
| Units available | 300 + 100 | 400 |
| Sell-through rate | 240 ÷ 400 | 60% |
| Units remaining | 400 − 240 | 160 |
| Units sold per week | 240 ÷ 28 days × 7 | 60 |
| Weeks of cover | 160 ÷ 60 | 2.7 weeks |
The product sold 60% of the units it had. At 60 units a week, the 160 units left last 2.7 weeks. If the supplier needs longer than that to deliver, the product runs out before the next delivery lands.
What each number means
Four numbers, and the decision each one informs.
Sell-through rate
Units sold ÷ units available. A low rate means stock is sitting, a high rate means the product sells quickly. Decision: whether to look for a slow product or to reorder.
Units remaining
Units available − units sold: what is left on the shelf. Decision: how much stock a clearance or an exposure plan has to move.
Weeks of cover
Units remaining ÷ units sold per week: how long the stock lasts at this period’s sales rate. Decision: whether to reorder now, read next to your supplier’s lead time.
Limits
What sell-through rate cannot tell you, and what to read next to it.
Which products are slow
A total across your products lets fast sellers hide slow ones. Work it out per product, or per category at least.
How long the period was
60% in 28 days and 60% in 90 days describe different selling speeds. Compare the same period and the same base each time.
What demand does next
Weeks of cover assumes this period’s sales rate continues. It misleads when demand is rising, falling or seasonal.
Why a product sells slowly
A product nobody sees needs exposure. One that many click but few buy may need lower priority. Sell-through shows the symptom, not the cause.
This calculator works on the numbers you enter. Inventory Insights shows projected demand, lead time, safety buffer, stock cover, reorder dates and slow stock with the reason it is slow, per product.
Sell-through rate questions, answered.
How do you calculate sell-through rate?
Divide the units sold in a period by the units available, then multiply by 100. Units available are the beginning inventory plus the units received. With 300 units at the start, 100 received and 240 sold, that is 240 ÷ 400 = 60%.
What is a good sell-through rate?
There is no universal figure: the rate depends on the length of the period, the category, the season and any promotion that ran. Compare a product with its own earlier periods of the same length and with similar products, counting units available the same way each time.
How do you work out weeks of cover?
Divide the units remaining by the units sold per week. The 160 units left at 60 a week last 160 ÷ 60 = 2.7 weeks. Compare that with how long your supplier needs to deliver.
What is the difference between sell-through rate and inventory turnover?
Sell-through rate divides units sold by units available (beginning inventory plus units received) in a period, as a percentage, and suits a shorter period or a single delivery. Inventory turnover divides cost of goods sold by average inventory at cost, usually over a year, so it counts how often the stock value sells.
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See which stock sells and which sits, product by product.
Inventory Insights shows stock cover, reorder dates and slow stock with its reason for each product. Stock cover feeds Product Score and reaches Merchant Center as a custom label you approve.
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