function calculateSellThroughRate() {
// Clear previous errors
var errorDiv = document.getElementById('str_error');
errorDiv.style.display = 'none';
errorDiv.innerText = ";
// Get Inputs
var unitsSoldInput = document.getElementById('str_units_sold').value;
var beginningInvInput = document.getElementById('str_beginning_inventory').value;
// Validate Inputs
if (unitsSoldInput === " || beginningInvInput === ") {
errorDiv.innerText = "Please enter both Units Sold and Beginning Inventory.";
errorDiv.style.display = 'block';
document.getElementById('str_result').style.display = 'none';
return;
}
var unitsSold = parseFloat(unitsSoldInput);
var beginningInv = parseFloat(beginningInvInput);
// Logic Checks
if (isNaN(unitsSold) || isNaN(beginningInv)) {
errorDiv.innerText = "Please enter valid numeric values.";
errorDiv.style.display = 'block';
return;
}
if (beginningInv <= 0) {
errorDiv.innerText = "Beginning Inventory must be greater than zero.";
errorDiv.style.display = 'block';
return;
}
if (unitsSold 80) {
velocityText = "Very High";
summaryText = "You are selling inventory extremely fast. While this indicates high demand, be cautious of potential stockouts.";
color = "#2980b9";
} else if (sellThroughRate >= 40 && sellThroughRate = 10 && sellThroughRate beginningInv) {
summaryText = "Note: Units Sold exceeds Beginning Inventory. This implies restocking occurred during the period.";
remainingStock = 0; // Or technically negative regarding the initial batch
}
// Update DOM
document.getElementById('str_output_percentage').innerText = sellThroughRate.toFixed(2) + "%";
document.getElementById('str_output_percentage').style.color = color;
document.getElementById('str_output_remaining').innerText = remainingStock < 0 ? 0 : remainingStock;
document.getElementById('str_output_velocity').innerText = velocityText;
document.getElementById('str_output_velocity').style.color = color;
document.getElementById('str_output_summary').innerText = summaryText;
// Show Result
document.getElementById('str_result').style.display = 'block';
}
Optimize Inventory with the Sell-Through Rate Calculator
Effective inventory management is the backbone of any successful retail or e-commerce business. The Sell-Through Rate (STR) is one of the most critical Key Performance Indicators (KPIs) you can track. It measures the efficiency of your supply chain by calculating the percentage of inventory sold versus the amount of inventory received within a specific period.
The Formula: Sell-Through Rate = (Units Sold / Beginning Inventory) × 100
Why is Sell-Through Rate Important?
Understanding your STR allows you to make data-driven decisions regarding purchasing, manufacturing, and marketing. A precise calculation helps you avoid two major retail pitfalls:
Overstocking: Having too much capital tied up in slow-moving goods increases storage costs and reduces cash flow.
Understocking: Running out of popular items leads to missed sales opportunities and dissatisfied customers.
How to Interpret Your Results
While benchmarks vary by industry (e.g., luxury fashion moves slower than FMCG), general guidelines include:
High STR (>80%): Your product is in high demand. While this is great for revenue, it poses a risk of stockouts. You may need to increase order quantities or reorder frequency.
Healthy STR (40% – 80%): This is generally considered the ideal range. It indicates you are buying the right amount of stock to meet demand without carrying excessive overhead.
Low STR (<40%): This suggests you have overbought or the product is not resonating with customers. You may need to implement discounts, bundle deals, or marketing campaigns to clear this inventory.
Strategies to Improve Your Sell-Through Rate
If our calculator shows a number lower than your target, consider these strategies:
Dynamic Pricing: Use small discounts to incentivize purchases on stagnant items before they become obsolete.
Product Bundling: Pair slow-moving items with best-sellers to increase their perceived value.
Visual Merchandising: Improve product photography and placement (both in-store and online) to increase visibility.
Demand Forecasting: Use historical sales data to adjust your future "Beginning Inventory" levels to match realistic demand.
Use this tool monthly or seasonally to keep a pulse on your inventory health and ensure your capital is working efficiently for your business.