What is sell-through rate?
Sell-through rate measures how quickly inventory received during a period converts into sales. It is expressed as a percentage: a 70% STR means 70 out of every 100 units received were sold during the same period, leaving 30 units unsold.
STR is a core metric in retail, ecommerce, wholesale, and inventory planning because it connects buying decisions directly to demand. Inventory that does not sell quickly ties up working capital, takes up storage space, and creates markdown risk — especially for seasonal or trend-sensitive products.
The metric sits between two types of risk: buying too little (stockouts, missed sales) and buying too much (unsold stock, markdowns, write-offs). A well-calibrated STR target helps teams walk that line.
Sell-through rate formula
The standard formula is:
Units Received = inventory brought in during that same period
Result = percentage of received inventory that sold
Both inputs must cover the same time window. Mixing units sold from one month against inventory received over a quarter is one of the most common calculation errors.
Full delivery waterfall
For a store that receives 600 units, sells 420, with each unit costing $18:
How to calculate sell-through rate — step by step
Worked examples
Four scenarios across different performance levels — strong, moderate, low, and above 100%.
High-demand product launch
A product line receives 1,000 units and sells 820 in the month.
Ending inventory: 180 units (18% unsold).
✓ Strong sell-through — consider replenishment planning.
Standard retail month
A store receives 600 units and sells 330 units.
Ending inventory: 270 units (45% unsold).
→ Acceptable in some categories — review against target.
Slow seasonal item
A seasonal item receives 400 units and sells only 80 units.
Ending inventory: 320 units (80% unsold).
✕ Low STR — possible overbuying or weak demand. Consider promotion or markdown.
Sales include prior-period stock
A store receives 150 units but sells 180 — drawing from older inventory.
Units sold exceeded received — carryover stock was liquidated.
→ Over 100% signals prior stock drawdown — review with total stock view.
Sell-through rate benchmarks by category
There is no universal "good" STR — the right level depends on category, seasonality, margin structure, replenishment lead time, and business model. These are common reference ranges used in retail and inventory planning.
By category
Sell-through rate vs inventory turnover vs service level
These three metrics all relate to inventory and performance but they measure fundamentally different things. Using the wrong metric for a decision is a common planning mistake.
A practical distinction: STR answers "how much of what arrived actually sold?", inventory turnover answers "how efficiently is total stock being cycled?", and service level answers "how often did we have stock when a customer needed it?"
Common mistakes to avoid
- Mixing time periods. Units sold and units received must cover the same window. Comparing January sales to Q1 received inventory produces a meaningless result.
- Confusing received inventory with beginning inventory. Some reporting systems track total stock on hand (including carry-forward); others track only new receipts. STR uses received inventory — clarify which your system exports.
- Interpreting very high STR without context. An STR above 95% may look excellent but could mean you consistently understock and miss sales. Pair STR with stockout frequency data.
- Ignoring markdowns and promotions in the STR signal. A spike in STR after a discount event tells you pricing drove velocity — not organic demand. Track whether promotional STR is sustainable at full price.
- Reviewing STR in isolation. STR should be read alongside gross margin, weeks of supply, and service level to give a balanced picture of inventory health. A high STR at terrible margin is not a win.
- Using the wrong denominator. Some teams accidentally divide by total available inventory (beginning stock + receipts) instead of just receipts. This consistently understates the true sell-through for new stock.
FAQ
What is the sell-through rate formula?
Sell-through rate equals units sold divided by units received, multiplied by 100. Example: selling 420 units from 600 received gives STR = 420 ÷ 600 × 100 = 70%.
Can sell-through rate be over 100%?
Yes. This happens when units sold during the period include carryover stock from a prior period — the denominator (units received this period) is smaller than total units sold. It signals prior inventory was drawn down, not that 100% of new stock sold.
Is sell-through rate the same as inventory turnover?
No. Sell-through rate is a percentage of received inventory sold within a period. Inventory turnover is a ratio showing how many times average inventory was cycled over a period, calculated using COGS and average inventory balance. They measure different things and serve different analytical purposes.
What is a good sell-through rate?
It depends heavily on category and seasonality. Fast fashion and perishables typically target 85–95%+. General ecommerce commonly runs 65–85%. Durable goods may operate at 40–65% without concern. The key is comparing against a relevant category benchmark and your own business targets, not a universal number.
How often should sell-through rate be measured?
It depends on the sales cycle. Fast-moving consumer goods and apparel are often tracked weekly during a season. General ecommerce SKUs may be reviewed monthly. Slow-moving durable goods might be reviewed quarterly. The measurement cadence should match the speed at which restocking or markdown decisions need to be made.
Should I use beginning inventory or received inventory as the denominator?
For the standard sell-through rate formula, use units received during the measurement period — not total beginning stock, which includes carry-forward from prior periods. If your reporting exports total available inventory, you are calculating a different (and broader) version of the metric. Align your formula with your reporting system.