Sell Through Rate Calculator

Calculate Sell Through Rate in Seconds — Free Tool

Calculate your sell through rate and uncover hidden cash tied up in unsold stock. Make smarter buying decisions and protect your margins — free, fast, and accurate.

Beginning inventory or stock received
Total units sold in the period
Time window for the calculation
Optional — for stock value
0.0% Sell-Through Rate
Remaining Stock
Sales per Day
Days of Inventory
Unsold Stock Value

Frequently Asked Questions

Use our free Sell Through Rate Calculator to measure inventory performance instantly. Input units received and sold — get your STR, days of stock, and sales velocity fast.

Q1: What is sell through rate and why does it matter?

A: Sell through rate (STR) is the percentage of inventory sold within a given period, calculated as: (Units Sold ÷ Units Received) × 100. It tells you exactly how fast your stock moves. A low STR means cash is sitting idle on your shelves. A high STR signals strong demand and healthy inventory turnover — both critical to protecting your margins.

Q2: How do you calculate sell through rate percentage?

A: The sell through rate formula is straightforward:

STR (%) = (Units Sold ÷ Units Received) × 100

Example: You received 100 units and sold 65 in 30 days. Your sell through rate = 65%. Use this calculator to get that number — plus remaining stock, sales per day, and days of inventory — in one click.

Q3: What is a good sell through rate for retail?

A: Most retail benchmarks target an STR between 70%–85% per period. Below 50% typically signals overstocking or weak demand. Above 90% can mean you're leaving sales on the table due to stockouts. The right target depends on your product category, seasonality, and reorder lead time.

Q4: How many days of inventory do I have left?

A: This calculator shows your days of inventory automatically. The formula is:

Days of Inventory = Remaining Stock ÷ Sales Per Day

In the example above: 35 remaining units ÷ 2.2 units/day = ~16 days of stock left. That's your reorder window — use it to plan purchases before you hit zero.

Q5: How does sell through rate affect cash flow?

A: Every unsold unit is frozen cash. If your STR is low, you're funding inventory that isn't generating revenue. Tracking your sell through rate weekly or monthly lets you spot slow-moving SKUs early, discount strategically, and free up working capital — which is the core principle behind lean inventory and FIRE-aligned business management.

Q6: How does changing the period length affect my sell through rate calculation?

A: The period (days) field adjusts your sales velocity (units per day) and days of inventory remaining — but it does not change the STR percentage itself. STR is purely units sold vs. units received. Changing the period helps you benchmark performance across different timeframes: weekly sprints vs. monthly cycles vs. quarterly reviews.

Q7: What does unsold stock value tell me?

A: When you enter a cost per unit, the calculator multiplies it by remaining stock to show your unsold stock value — the exact dollar amount tied up in inventory. This figure is critical for cash flow planning, write-off decisions, and end-of-season clearance pricing. If that number is growing period over period, your buying strategy needs adjustment.

Q8: Can I use this calculator for e-commerce and Amazon FBA?

A: Yes. The sell through rate calculator works for any product-based business: brick-and-mortar retail, Amazon FBA, Shopify stores, wholesale, and subscription boxes. Amazon itself uses STR to evaluate FBA storage efficiency — sellers with low sell-through rates may face higher storage fees or restock limits. Knowing your STR before Amazon flags it gives you a critical operational edge.