Sell-through rate: formula, why sources disagree, and a calculator.
Sell-through rate compares how many comparable items sold with how many are available. Enter your counts and the window they cover to see the rate and the months of inventory at that pace. It is an estimate from your own numbers.
Sources verified October 8, 2026. Carrier rules and prices change, so confirm with the carrier or eBay before you ship. Report an error
Sell-through rate calculator
Count comparable sold items for a window you choose and comparable listings active now. Values stay in your browser and are not saved.
The formulas, and the one this page uses
The same steps run in the calculator above and are written out here for anyone reading without JavaScript.
This page leads with sold divided by sold plus active. It reads as the share of the comparable items counted that sold, it always lands between 0 and 100 percent, and it stays defined when nothing is listed right now. The other common reading is sold divided by active:
That version can pass 100 percent when more items sold in the window than are listed today, which some people read as demand outrunning supply. Pick the second option in the calculator to see it. The two formulas give different numbers for the same counts, so compare a rate only with another rate that uses the same formula and window.
Months of inventory turns the window into a monthly pace, using a 30 day month, and divides the listings now for sale by that pace. It is the same for both formulas, and it is not defined when nothing sold.
| Step | Result |
|---|---|
| Sold in the window | 30 items over 90 days |
| Active now | 60 items |
| Sold / (sold + active) | 33.3% |
| Sold / active | 50.0% |
| Sold per 30 day month | 10 items |
| Months of inventory | 6 months |
Why sources disagree
eBay's Product research help page lists a "Sell through rate (for searches of items sold 90 days ago or less)" among the data it gives sellers with access to Seller Hub.1 That page names the metric and its window but does not state a formula, so a count of your own cannot be used to reproduce eBay's figure.
Elsewhere, formulas vary. Rates can differ because of the formula, the window, the way a tool matches items as comparable, and whether the active count is taken at the same time as the sold count. Active listings are a snapshot of today, while sold items are collected over a period, so even a clean formula mixes two kinds of count. Treat a sell-through rate as one signal next to sold prices and your own sales history, and keep the same method when you compare items.
Sell-through rate questions
What is sell-through rate?
It compares how many comparable items sold in a period with how many are available. A higher rate generally points to stronger demand for that kind of item, but it depends on which items you count and over what period.
What is the sell-through rate formula?
Two readings are common. Sold divided by sold plus active stays between 0 and 100 percent. Sold divided by active can pass 100 percent when more items sold than are listed. This page leads with sold divided by sold plus active and lets you switch.
Why do sell-through rates differ between sources?
Formulas vary, and so do the windows and the matching rules. Two tools can count a different period, a different set of comparable items, or a different denominator, so compare a rate only with rates from the same source and settings. eBay's Product research help page names a sell through rate but does not publish its formula there.
What does eBay say about sell-through rate?
eBay's Product research help page lists a sell through rate for searches of items sold 90 days ago or less among the data it gives sellers with access to Seller Hub. The page does not state a formula, so this calculator cannot reproduce eBay's number from counts.
What are months of inventory?
It is the active count divided by items sold per month, where the monthly pace is the sold count spread over your window and scaled to a 30 day month. It estimates how long the listings now for sale would take to sell if the pace stayed the same.
How accurate is the result?
It is an estimate from the counts you enter. Sold and active counts are taken at different times, the match quality of the items you count matters, and demand shifts with the season. Treat the result as one signal next to sold prices and your own sales history.
Where these facts come from
- eBay, Product research, www.ebay.com/help/selling/selling-tools/product-research?id=4853 (verified October 8, 2026)
Check the sell-through, then see comps and estimated profit before you buy
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