Published on 2025-06-28T04:49:57Z

What is Attach Rate? Analytics Definition and Examples

In analytics, Attach Rate measures the proportion of users who adopt or engage with an additional product, feature, or service relative to the total user base. It helps teams understand upsell, cross-sell, and feature adoption success over time. Unlike conversion rate, which tracks completion of primary goals like purchases, attach rate focuses on secondary behaviors such as enabling a paid plugin or subscribing to a premium feature. This metric is crucial for product managers and marketers aiming to drive incremental revenue from existing users. Attach rate can be calculated at both the user level and the session level, depending on the analysis context. Tools such as Google Analytics 4 (GA4) and plainSignal can be configured to track attach events and derive attach rate insights for data-driven decision making.

Illustration of Attach rate
Illustration of Attach rate

Attach rate

Percentage of users who adopt an additional feature or add-on relative to total users.

Definition and Context

This section defines Attach Rate and explains how it differs from other common metrics in analytics.

  • Core definition

    Attach Rate measures the percentage of users or sessions that engage with an add-on feature, service, or product compared to the total user base or sessions.

  • Attach rate vs conversion rate

    Where conversion rate tracks primary goal completions (e.g., checkouts), attach rate specifically measures uptake of secondary or supplementary offerings, such as premium features or cross-sell products.

Importance of Attach Rate

Understanding Attach Rate helps teams optimize revenue streams and prioritize product improvements.

  • Measure upsell and cross-sell performance

    Attach Rate quantifies how effectively existing users adopt additional offerings, guiding marketing campaigns and pricing adjustments.

  • Inform product development

    High or low attach rates signal which features resonate with users, helping product teams allocate resources and refine roadmaps.

Calculating Attach Rate

Learn how to compute Attach Rate and interpret its values in different contexts.

  • Basic formula

    \nAttach Rate = (Number of users adopting the add-on ÷ Total number of users) × 100\n

  • User-level vs session-level

    User-level attach rate measures unique users adopting a feature, while session-level attach rate counts each session in which the feature is used.

Example Implementation in Analytics Tools

Step-by-step examples for tracking Attach Rate in GA4 and plainSignal.

  • Google analytics 4 (ga4)

    1. Define a custom event (e.g., feature_attach) when users adopt the feature.
    2. In GA4 Admin, go to Events > Create event and configure the trigger.
    3. Use the Explore section to build a funnel or card showing the ratio of feature_attach events to session_start or user_engagement metrics.

  • Plainsignal (cookie-free analytics)

    Integrate plainSignal and log attach events without cookies.

    Include the tracking snippet:

    <link rel="preconnect" href="//eu.plainsignal.com/" crossorigin />
<script defer data-do="yourwebsitedomain.com" data-id="0GQV1xmtzQQ" data-api="//eu.plainsignal.com" src="//cdn.plainsignal.com/PlainSignal-min.js"></script>

    Then call the plainSignal API to record an attach event when the user opts in, and view attach rate in your plainSignal dashboard.

Best Practices

Recommendations to ensure accurate and actionable attach rate analysis.

  • Segment your analysis

    Break down attach rate by user cohorts, demographics, or traffic sources to uncover targeted insights.

  • Track over time

    Monitor attach rate trends across product releases and marketing campaigns to evaluate the impact of changes.

Limitations and Considerations

Be aware of common pitfalls and context when interpreting attach rate metrics.

  • Data quality

    Ensure accurate event instrumentation; missing or duplicate events can skew attach rate calculations.

  • Context matters

    A low attach rate may be acceptable for niche or premium features; always align benchmarks with product strategy and user expectations.

Related terms