Sell-Through Rate Calculator
Enter units sold and beginning inventory received to calculate sell-through rate, unsold inventory, unsold rate, target gap, units needed to hit your target, and the cost tied to unsold stock — all in one view.
Enter inventory values
Sell-through rate shows what percentage of received inventory sold during a period. Use it to evaluate demand velocity, restocking timing, markdown risk, and product performance.
What is sell-through rate?
Sell-through rate (STR) measures the percentage of received inventory that was sold during a given period. It is a straightforward gauge of how quickly a product is moving and whether inventory levels are well-matched to customer demand.
A higher sell-through rate signals strong demand or lean inventory positioning. A lower rate may indicate slow sales velocity, overbuying relative to demand, weak promotion, or a seasonal mismatch. Both extremes carry risk — too high may mean stockouts and missed sales, too low means tied-up capital and potential markdowns.
Sell-through rate formula
The core formula is:
Additional metrics this calculator derives:
How to use this sell-through rate calculator
- Enter the number of units sold during the measurement period.
- Add the beginning inventory or units received for that same period.
- Optionally set a target sell-through rate to see how actual performance compares.
- Add unit cost to estimate the dollar value of unsold inventory.
- Click Calculate to see sell-through rate, unsold inventory, target gap, and more.
Example calculation
A store receives 600 units of a new product and sells 420 units during the month.
Ending inventory is 180 units and the unsold rate is 30%. If each unit cost $18, the unsold inventory has $3,240 of capital tied up:
If the target rate was 75%, the target gap is 70% − 75% = −5 pts, meaning 30 more units need to sell to reach the planned rate.
Why sell-through rate matters
Sell-through rate connects merchandising decisions directly to demand data. Teams use it to:
- Decide when to reorder, discount, bundle, or stop replenishing a product
- Identify fast-moving winners and slow movers early in a season
- Improve cash flow planning by reducing capital tied to stagnant inventory
- Set category-level benchmarks and compare SKU performance within a range
- Time markdown decisions before end-of-season to minimize margin loss
For seasonal products — fashion, holiday goods, perishables — sell-through rate is especially critical because unsold inventory after a season has very limited recovery value.
What counts as a good sell-through rate?
Benchmarks vary significantly by category, margin structure, replenishment speed, and seasonality. A general orientation:
- 80%+ STR — strong performance in most categories; consider replenishment
- 60–80% STR — acceptable in many retail contexts; review against category target
- 40–60% STR — moderate concern; investigate demand drivers or promotion
- Below 40% STR — significant unsold inventory; may need markdown or re-allocation
Fast-fashion and perishable categories often target 85–95%+ because unsold inventory has little residual value. Durable goods with longer shelf life may tolerate lower rates.
FAQ
Is a higher sell-through rate always better?
Not always. A very high STR — close to 100% — can indicate you underbought and left potential sales on the table due to stockouts. The ideal rate balances selling most of your inventory while maintaining enough buffer to avoid running out before the period ends.
Should I use beginning inventory or average inventory?
For sell-through rate, most retailers use beginning inventory or units received during the period as the denominator. Average inventory is more common for inventory turnover ratio calculations. Align your formula with how your reporting system defines the base.
What is the difference between sell-through rate and inventory turnover?
Sell-through rate is a percentage — it tells you what share of inventory sold. Inventory turnover is a ratio — it tells you how many times inventory was replaced over a period. STR is better for evaluating a single SKU or product line within a period; turnover is better for comparing overall stock velocity across periods.
Can units sold exceed received inventory in this calculator?
No — this calculator treats units sold as a share of beginning inventory received within the same period. If your units sold exceed received inventory, your inputs likely mix periods or exclude carryover stock from a prior period.
How often should sell-through rate be measured?
It depends on the product and sales cycle. Fast-moving consumer goods may be tracked weekly. Seasonal fashion categories are often tracked monthly and reviewed at mid-season checkpoints. Slow-moving durable goods may be reviewed quarterly.
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Disclaimer
This calculator is for educational and planning purposes only. Actual inventory reporting methods may vary by business, accounting policy, and software setup. Always align the formula with the inventory definition used in your own reports.