You bought ten of a dress and sold eight. You bought forty of a top and sold twelve. Which one performed better? Most owners answer "the top" — it sold more. But the dress cleared 80% of what you paid for, and the top left 28 units and most of your cash sitting on a rack. That gap is what sell-through measures, and it's why it's the number that should drive your reorders.
I'm Carina Hatton — boutique owner since 2013, ecommerce coach since 2019. This is the post-purchase half of buying: the inventory has landed, some of it is moving, and now you have to decide what deserves more money. Nothing here is a benchmark you should adopt on faith. The numbers are arithmetic; the judgment stays yours.
What sell-through rate actually is
Sell-through rate is the percentage of the units you received that have sold. One formula, no variations worth arguing about:
Sell-through % = units sold ÷ units received × 100
Received twelve, sold nine, that's 75%. The important part isn't the arithmetic — it's what the number represents. When you place a wholesale order, you convert cash into product. Sell-through tells you what proportion of that specific conversion has turned back into cash. It's a per-product read, not a store-wide one. Averaging your whole store together produces a number that hides both your winners and your problems, which makes it useless for the decision you're actually trying to make.
Two practical notes on the inputs. Units received means what you actually took in and could sell — if half the order arrived damaged, those units never had a chance to sell and shouldn't sit in the denominator making the style look worse than it is. And if you restocked mid-way, decide up front whether you're measuring the original buy or the style overall, then stay consistent.
Sell-through means nothing without a time window
Here's the mistake that makes sell-through useless: quoting the percentage without the period it happened over.
Ten units sold in seven days and ten units sold in ninety days are the same units sold. They are not remotely the same product. The first is moving faster than you can restock it; the second has been quietly occupying space for three months. If someone tells you a style is "at 60%," your next question should always be over how long?
So sell-through needs two companions to become decision-grade:
- Days in stock — how long the product has genuinely been available to buy. Not days since you ordered it, and not days since the box arrived. Days since it was photographed, listed, priced, and findable. A style that sat unphotographed for three weeks didn't underperform for three weeks; it didn't exist.
- Units sold per week — your rate of sale. This is what converts a static percentage into a speed.
- Weeks of supply remaining — how long what's left will last at that speed. This is the number that actually connects to a decision, because it's the one you can compare against your supplier's lead time and your season.
I'm not going to give you a target for any of these, because a target that's right for a $18 hair claw is wrong for a $180 coat, and one that's right in November is wrong in January. What's portable is the structure, not the thresholds.
The four numbers, in order
Each one builds on the last:
| Number | Formula | What it tells you |
|---|---|---|
| Sell-through % | Units sold ÷ units received × 100 | How much of this buy has cleared |
| Units per week | Units sold ÷ (days in stock ÷ 7) | How fast it's selling |
| Weeks of supply | Units remaining ÷ units per week | How long what's left will last |
| Projected sell-out | Weeks of supply × 7 | Roughly when you run out |
Worked example. You received 10 units, sold 8, and it's been in stock 28 days. Sell-through is 8 ÷ 10 × 100 = 80%. Twenty-eight days is four weeks, so you're selling 8 ÷ 4 = 2 units per week. You have 2 units left, so weeks of supply is 2 ÷ 2 = 1 week — about seven more days before you're out.
"Projected sell-out" deserves a plain-language caveat, because the phrase sounds more confident than the maths deserves. It isn't a forecast. It's a projection that assumes the last few weeks repeat exactly: no promo, no post that takes off, no cold snap, no competitor undercutting you. Treat it as "here's what happens if nothing changes," which is useful precisely because something usually does.
The Sell-Through & Reorder Calculator runs all four and handles the awkward cases — zero sales, sold-out styles, a brand-new product with barely any history.
Why units sold alone can mislead you
This is the single most expensive misread in boutique buying, so it's worth sitting with.
Go back to the two products. The dress: 10 received, 8 sold in four weeks. The top: 40 received, 12 sold in the same four weeks.
| Dress | Top | |
|---|---|---|
| Units received | 10 | 40 |
| Units sold (4 weeks) | 8 | 12 |
| Sell-through | 80% | 30% |
| Units per week | 2 | 3 |
| Units still on the rack | 2 | 28 |
| Weeks of supply left | 1 | ~9.3 |
Sort your bestseller report by units sold and the top wins — it moved more pieces and probably more revenue. That report is not wrong, it's just answering a different question. Sorted by sell-through, the dress wins decisively: it cleared 80% of its buy and is about to sell out, while the top has more than two months of supply sitting in the building at its current pace.
Notice something important, though: the top actually sells faster per week. Three units to the dress's two. This is why sell-through alone isn't the whole answer either — it's heavily shaped by how deep you bought. Buy shallow enough and almost anything posts a strong sell-through; buy forty units of something and you've mathematically guaranteed a low one for a while.
So the honest reading of the pair is: units sold measures demand, sell-through measures how well your buying decision matched that demand, and rate of sale is what you carry forward. The dress didn't sell faster — you just bought it in a quantity that fit. The top may be a perfectly good product that you simply bought too deep. Those two conclusions lead to completely different actions, and you can't tell them apart from either number alone.
Practically: use sell-through to judge the buy, use units per week to judge the product, and use weeks of supply to judge the timing.
Should you reorder this product?
There's no percentage that answers this. What there is, is a short list of questions — and the reorder case gets stronger or weaker depending on how they land.
What strengthens the case
- It sold at full price. No discount was needed to move the units. This is the cleanest demand signal you get.
- Demand is steady or accelerating. Compare the last two weeks against the two before them. A rising rate means your average rate of sale is understating the product.
- Weeks of supply is running short against your lead time. If what's left won't outlast the vendor's shipping time, the decision window is closing whether you engage with it or not.
- The selling season still has real length left, or the item isn't seasonal at all.
- The vendor can actually replenish it. Obvious, routinely skipped. Plenty of reorder analysis has been done on styles that were already discontinued.
- The margin holds up. A fast seller you barely make money on is a different proposition than a fast seller with room in it. Check it in the Profit Margin Calculator if you haven't lately.
What weakens it
- It needed a markdown to move. More on this below — it's the factor owners most often gloss over.
- Demand is slowing. An average rate of sale flatters a decelerating product, because the strong early weeks are still in the average. The remaining stock will likely last longer than projected.
- Supply comfortably outlasts the replenishment window. You have time. Watching costs nothing; committing does.
- The season closes before the stock clears. If projected sell-out lands past the end of the selling window, more depth is the wrong direction — clearing what you have is the live question instead.
- The sell-through is flattered by a tiny buy. Three units received and three sold is 100% and tells you almost nothing. It's a signal to test wider, not proof of a winner.
Note what none of these are: a score, a cutoff, or a rule that fires automatically. Two owners can look at identical numbers and correctly reach opposite decisions, because one has cash committed elsewhere and the other doesn't. The framework's job is to make sure you've looked at all the factors, not to make the call for you.
A middle option gets forgotten too often: reorder shallower. "Reorder" and "don't reorder" aren't the only moves. Reducing depth on a style you believe in but can't fully read yet is frequently the most honest answer.
The markdown-dependence trap
A style sits for six weeks. You put it at 30% off. It clears in ten days. Your sell-through report now shows a healthy number and the style looks like a winner.
Read that carefully, because there's a real possibility the markdown sold the item rather than the product proving full-price demand. What you've learned is that customers will buy it at the discounted price — which is genuinely useful information, just not the information a reorder decision needs. Reorder on the strength of a discounted sell-through and you can end up buying more of something that only ever works on sale, at a margin you didn't plan for.
Frame it as context, not a verdict. Sometimes the markdown was a merchandising fix — the product was buried, the photos were weak, it wasn't styled with anything — and the discount simply bought it the attention it should have had. Sometimes the price was just wrong for your customer, and the "discounted" price is actually the correct one, which is a pricing lesson rather than a product failure.
The useful move is to separate the two periods. What did it do per week before the markdown, and what did it do after? If it was moving reasonably at full price and the discount just accelerated the tail, that's a very different product than one that did nothing for six weeks and only responded to a price cut.
Sell-through tells you whether; open-to-buy tells you whether you can
These two run in sequence, and the order matters.
Sell-through answers: should I reorder this? It's a product question, answered with product data.
Open-to-buy answers: can I afford to reorder anything right now? It's a plan question, answered in retail dollars across your whole buy.
Do the product work first. Identify what's earned more money, then take that shortlist to your buying budget and see what fits. Running it the other way — checking your open-to-buy first and then looking for things to spend it on — is how a positive OTB number turns into permission to repeat last month's mistakes. The full monthly method is in open-to-buy for small boutiques, and the Open-to-Buy Calculator runs the formula.
One practical consequence: a style can be a genuinely strong reorder candidate and still not get reordered this month, because the money isn't there. That's not a failure of analysis. It's the two questions doing their separate jobs.
When the answer isn't a reorder
If a product isn't a reorder candidate, you still own the units. The next decision is what it takes to convert them back into cash, and at what cost to your profit.
That's a margin question before it's a discount question. The discount that moves the stock and the discount that leaves you profitable aren't automatically the same number, and the gap between them is exactly what you need to see before you announce a sale. Work it through in the Markdown Calculator — it accounts for fees and shipping, shows what the margin looks like after the discount, and tells you the deepest discount that still clears the minimum margin you're willing to accept.
Two things worth holding onto. First, the money you spent on that inventory is already spent — the only live question is what you can still recover and how much longer you want the space and cash tied up. Second, a markdown is information: what a style needed in order to move is worth writing down next to the vendor's name, because that's how the next buy gets better.
Making it a habit
Sell-through only works if you look at it on a rhythm rather than in a panic. Pick a cadence you'll actually keep — weekly is plenty for most boutiques — and review new receipts at a fixed point after they land, not whenever the storage room starts to feel full. Set the review date when you place the order.
The tracking system, the spreadsheet columns, and the rest of the metrics that sit around this one live in boutique inventory management. And if the buy you're evaluating hasn't been placed yet, sizing that is a different job — the Inventory Buy Planner handles the before, this article handles the after.
Run one style through the Sell-Through & Reorder Calculator right now — pick the one you've been unsure about — and see what four honest numbers do to the conversation you've been having with yourself about it.
— Carina