Measure your cross-selling and up-selling efficiency
The main product count (denominator)
The accessory or add-on count (numerator)
Your Attach Rate is
0%
function calculateAttachRate() {
// Get input elements by exact ID
var primaryInput = document.getElementById('primaryUnits');
var secondaryInput = document.getElementById('secondaryUnits');
var resultBox = document.getElementById('resultBox');
var resultText = document.getElementById('attachResult');
var resultExplanation = document.getElementById('resultExplanation');
var errorDisplay = document.getElementById('errorDisplay');
// Parse values
var primary = parseFloat(primaryInput.value);
var secondary = parseFloat(secondaryInput.value);
// Reset display
errorDisplay.style.display = 'none';
resultBox.style.display = 'none';
// Validation
if (isNaN(primary) || primary <= 0) {
errorDisplay.innerText = "Please enter a valid number of Primary Units greater than 0.";
errorDisplay.style.display = 'block';
return;
}
if (isNaN(secondary) || secondary 100) {
explanation += " Great Job! You are selling more than one add-on per primary product on average.";
} else if (rate < 5) {
explanation += " Opportunity: Your attach rate is low. Consider bundling strategies.";
}
resultExplanation.innerHTML = explanation;
resultBox.style.display = 'block';
}
How to Calculate Attach Rate
The Attach Rate is a critical key performance indicator (KPI) used in sales and marketing to measure the success of cross-selling strategies. It represents the frequency with which a secondary product (or add-on) is sold alongside a primary product.
Whether you are selling extended warranties for cars, cases for smartphones, or support packages for software, calculating your attach rate helps you understand customer behavior and the effectiveness of your sales team's bundling efforts.
The Attach Rate Formula
The math behind the attach rate is straightforward. It compares the volume of secondary items sold against the volume of primary items sold.
Formula: Attach Rate (%) = (Secondary Units Sold / Primary Units Sold) × 100
Step-by-Step Calculation
Identify the Primary Product: This is the main item driving the sale (e.g., a Game Console).
Identify the Secondary Product: This is the accessory or service tied to the main item (e.g., an Extra Controller).
Gather Sales Data: Determine the total units sold for both products over a specific time period.
Divide and Multiply: Divide the secondary units by the primary units and multiply by 100 to get a percentage.
Real-World Example
Let's say you run an electronics store. Last month, you sold the following:
Primary Product (Smartphones): 500 units
Secondary Product (Screen Protectors): 125 units
To calculate the attach rate for screen protectors:
(125 / 500) = 0.25 0.25 × 100 = 25%
This means 25% of your phone customers also bought a screen protector.
Can Attach Rate Exceed 100%?
Yes, absolutely. An attach rate over 100% indicates that, on average, customers are buying more than one accessory per primary unit. For example, if you sell 100 flashlights (Primary) and 300 batteries (Secondary), your attach rate is 300%. This is common for consumables or low-cost accessories.
Why This Metric Matters
Monitoring this metric allows businesses to:
Evaluate Sales Performance: Identify which sales representatives are effectively pitching add-ons.
Optimize Inventory: Ensure you have enough accessories to match the demand generated by primary product sales.
Increase Revenue: Secondary products often carry higher profit margins than the primary "hero" product.