Sell-through rate: the 8-week test for whether a delivery is doing its job.
Sell-through rate is units sold divided by units received, in the same window. A healthy boutique hits 70-80% within 8 weeks of a delivery. Below 50% means you bought too deep or priced too high — and the markdown clock has already started.
Sell-through rate is the percentage of a specific delivery that sold within a target window — usually 4 to 8 weeks. The formula is units sold divided by units received, in the same period, times 100. It is the most actionable inventory metric a small shop has, because the answer arrives early enough to do something about it. nouz shows COGS by SKU on every daily P&L so the sell-through math is a number you can read off the screen, not a spreadsheet you build at season-end.
TL;DR
Definition
Sell-through rate measures one delivery against itself. You bought 60 units of a style; 8 weeks later you have sold 45. Your 8-week sell-through is 75%. That is it.
It is different from inventory turnover, which is an annual shop-wide ratio. Turnover tells you how the whole shop performed last year. Sell-through tells you how the dress you bought six weeks ago is doing right now, while you still have time to react.
It is also the metric most tightly linked to markdown discipline. The sell-through curve in the first 8 weeks predicts whether a SKU will exit the shop at full price or whether it will need a 20%, 40% or end-of-season 60% markdown to clear. The earlier you read the curve, the cheaper the markdown.
The formula
Sell-through % = (Units sold / Units received) × 100The denominator is units received — not units on hand. If you received 60 in week 1 and another 20 in week 4, the denominator at week 8 is 80, not 60. Some shops use "units available" (received plus opening stock of the same SKU), which is fine as long as you stay consistent across SKUs.
The period is the part most often skipped. "75% sell-through" without a window is meaningless — 75% in 4 weeks is excellent, 75% in 26 weeks is bad. Always say "75% in 8 weeks."
Worked example
A boutique receives a 60-unit delivery of a summer dress on Monday week 1. Weekly sales:
| Week | Units sold this week | Cumulative sold | Cumulative sell-through |
|---|---|---|---|
| 1 | 12 | 12 | 20% |
| 2 | 10 | 22 | 37% |
| 3 | 8 | 30 | 50% |
| 4 | 6 | 36 | 60% |
| 5 | 5 | 41 | 68% |
| 6 | 4 | 45 | 75% |
| 7 | 3 | 48 | 80% |
| 8 | 3 | 51 | 85% |
85% at week 8. Healthy. The remaining 9 units will probably clear at a modest week 10-12 markdown of 20-30% with the gross margin still intact on average.
Compare to a delivery that sold 18 units in 8 weeks (30% sell-through). The cumulative curve flattens by week 3 instead of week 6, and the math forces a different decision — typically a 40-50% markdown by week 10 to free the shelf space and recover whatever cash you can. See spot and clear dead stock for the markdown calendar.
Benchmarks
| Category | 8-week healthy sell-through | Notes |
|---|---|---|
| Boutique apparel (in-season) | 70-80% | Markdown small remainder at week 10-12 |
| Fast fashion | 85-95% | Buy shallower than you think you need |
| Footwear (size matrix) | 55-70% | Wide sizes lag; clear stragglers at season-end |
| Homewares (seasonal) | 60-75% | Christmas/spring peaks dominate |
| Books (new release) | 40-60% | Long tail expected; 12-week window more realistic |
| Jewellery | 30-50% | Slow-cycle; 12-26 week window standard |
A boutique sitting at under 50% in 8 weeks on a fashion SKU is almost always either over-bought (took too many units) or over-priced (markup too aggressive for the customer). Both are diagnosable in week 3-4 — the curve flattens early.
Why it matters
Sell-through is the earliest signal of a buying problem. Annual turnover only tells you in December what you should have known in March. Sell-through tells you in week 4 what to do in week 5.
The economics are direct: a SKU that hits 70%+ sell-through in 8 weeks usually clears at full margin. A SKU that hits 30-50% needs a 20-40% markdown to clear, which destroys half the gross margin on the remaining units. A SKU at under 30% by week 8 will probably need a season-end clearance and may not cover its own COGS.
Reading the curve early is the difference between a 60% gross margin and a 35% gross margin on the same delivery. That gap is exactly the kind of margin leak the margin curve restock article documents in detail.
For repeat-buy decisions: sell-through is the single best input. If a style hit 80% in 8 weeks, reorder confidently. If it hit 45%, do not reorder — you already have the customer signal. The boutique turnover mastery article connects sell-through to the seasonal buying calendar.
Related concepts
- Inventory turnover — shop-wide annual ratio; sell-through is its per-delivery cousin.
- Dead stock — what the low-sell-through SKUs become if you ignore the 8-week signal.
- Margin curve and restock discipline — how to use sell-through to drive reorder decisions.
- Boutique inventory turnover mastery — the buying calendar that lifts sell-through across the season.
- GMROI — the capital-efficiency metric that sell-through ultimately feeds.
FAQ
What is a good sell-through rate for a small boutique?
70-80% in the first 8 weeks of a delivery is the healthy boutique range. Fast fashion targets 85-95% in 6-8 weeks. Footwear runs lower at 55-70% because the size matrix drags. Anything under 50% at week 8 in a fashion category is a buying or pricing problem and needs an early markdown to clear.
How is sell-through different from inventory turnover?
Sell-through is per-delivery and short-window (4-8 weeks). Turnover is shop-wide and annual. Sell-through gives you the early signal — turnover gives you the year-end scorecard. Both matter, but sell-through is the one you can act on while a decision is still cheap.
Should I measure sell-through in units or in revenue?
Units. Always units. Revenue-based sell-through is distorted by markdowns — a SKU that hit 70% sell-through at 40% off looks better in revenue terms than it should. Counting units cleanly separates "did it sell" from "did it sell at the price I wanted."
What window should I use for sell-through if my SKUs are slow-cycle?
Match the window to the category. 4-8 weeks for fashion. 8-12 weeks for seasonal homewares. 12-26 weeks for books, jewellery, or backlist categories. The principle holds across all: pick the window that lets you act on the answer while there is still time to reprice or reorder.