Sell-through rate answers one question: of the units you brought in, how many actually sold in the window? It is the fastest read on whether a buy was a hit or a mistake.
Sell-through rate is the percentage of available inventory that sold during a specific period, usually a month. It compares what you sold against what you had to sell, expressed as a percent. A 70% sell-through means you sold 70 of every 100 units you started the period with. A 20% sell-through means most of the batch is still sitting there.
It is a velocity metric scoped to a batch and a window, which makes it the natural read on a purchasing decision. You bought 500 units; a month later, how much of that buy moved? Sell-through tells you whether the order was sized right, priced right, and demanded.
Sell-through rate = (Units sold during the period / Units available at the start of the period) x 100.
"Units available at the start" usually means beginning inventory, the stock you had on hand when the period opened. Some sellers use units received in the period for newly launched products, which answers a slightly different question, how fast a fresh buy is moving. Pick one definition and stay consistent so your numbers compare across periods.
You start the month with 400 units of a SKU. During the month you sell 280.
Sell-through = (280 / 400) x 100 = 70%.
You moved 70% of the stock you held. The remaining 120 units carry into next month. If your reorder lead time is short and demand is steady, 70% in a month is a strong, healthy result. If those 120 units represent three more months of cover, the buy was too large.
There is no single target, because the right sell-through depends on your reorder cadence and lead time. The principle: sell-through should roughly match the share of your replenishment cycle the period covers.
The value is in the trend and the comparison across SKUs, not the absolute number. A SKU whose sell-through is sliding month over month is telling you demand is cooling before your turnover ratio or your cash position makes it obvious.
These two get confused constantly. They measure related but different things.
| METRIC | SCOPE | PERIOD | QUESTION IT ANSWERS |
| Sell-through rate | One batch or SKU | Short, often a month | What share of this stock sold in the window? |
| Inventory turnover (/glossary/inventory-turnover-ratio) | Whole inventory | Long, often a year | How many times did I cycle all inventory? |
Sell-through is the close-up: a specific buy, a specific month. Turnover is the wide shot: the whole portfolio over the year. You use sell-through to judge individual purchasing decisions and to time reorders. You use turnover to judge overall capital efficiency. Both rest on having an accurate count of what you sold and what you held.
Sell-through is only as honest as your inventory data. If you sell across channels and your "units available" figure ignores stock at a 3PL or in transit, the denominator is wrong and the rate is misleading. If you cannot cleanly attribute units sold to a SKU because returns and channel data are messy, the numerator is wrong too.
For multi-channel sellers, the count that feeds sell-through has to span every location and every channel. ConnectBooks supplies that base. ConnectStock, its multi-location inventory feature, tracks units across FBA, 3PL, home warehouse, and in transit, so the available-units figure is complete and the units-sold figure reconciles to settlement data. ConnectStock is bundled with Platinum and available as an add-on on Gold and Diamond. From a clean count, sell-through and reorder timing become reliable rather than guesswork, which is the subject of forecasting inventory reorders (/blog-posts/forecast-inventory-reorders).
For many fast-moving SKUs, a monthly sell-through of 60% to 80% is healthy. Above 90% can mean you are understocking; below 30% can mean overbuying or weak demand. The right target depends on your reorder lead time and cadence, so track the trend rather than chasing one number.
Sell-through measures the share of a specific batch sold in a short window, often a month. Turnover measures how many times you cycle your entire inventory over a long period, usually a year. Sell-through judges individual buys; turnover judges overall capital efficiency.
Either works, but stay consistent. Beginning inventory answers "how much of what I held sold." Units received answers "how fast a new buy is moving." Mixing them between periods breaks the comparison.
It should account for them. Returns reduce net units sold and can add units back to available stock. Ignoring returns overstates how much genuinely sold and distorts both the numerator and the available-units figure.
Usually because the available-units count is incomplete, often missing stock at a 3PL or in transit, or because units sold are not cleanly attributed across channels. A complete multi-location count, like the one ConnectStock maintains, fixes both sides of the ratio.
Calculate sell-through from a complete multi-location count, not a partial one. See ConnectStock at /pricing.
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