What is K-factor?

K-factor is a metric that measures how “viral” your app is. It measures how often existing users invite new ones, and whether those invites lead to installs, typically through trackable methods like referral links, in-app invitations, or shareable codes. 

K-factor helps you understand how users contribute to growth through sharing. It’s useful for measuring the effectiveness of referral programs and for identifying the indirect impact of paid campaigns on organic installs.

By tracking K-factor over time, you can evaluate how your app grows and make informed decisions about your user acquisition strategy. It also helps you optimize referral mechanics and budget allocation. Since K-factor can vary by region, timing, and user behavior, monitoring it regularly can reveal new growth opportunities.

A strong K-factor means users are actively helping grow your app, supporting long-term scalability.

The formula for calculating K-factor is:

K-factor helps you assess whether your app is shrinking, stable, or growing through referrals.

• K < 1: The app is shrinking. Each user brings in fewer than one new user, so the total number of users decreases over time.
• K = 1: The app is stable. Each user brings in exactly one new user, so the user base stays the same.
• K > 1: The app is growing. Each user brings in more than one new user, so the user base increases over time.

Example:

If the K-factor is 1.2 and you start with 100 users:

• After the first cycle, you’ll have 120 users.
• After the second cycle, 144 users.
• After the third cycle, 172.8 users.

Each cycle adds more users than the last.

K-factor measures growth driven by direct referrals, when existing users invite others to install the app. Organic growth, however, refers to installs that happen independently, without direct referrals. These typically come from search, App Store rankings, or being featured. Organic installs can also increase when paid campaigns improve visibility. K-factor does not account for this as it measures only user-to-user sharing.

To improve your app’s K-factor, you need to increase the number of users who send invites and the number of those invites that convert into new users.

1. Make sharing easy: Allow users to send invites with one tap. Use pre-filled messages, direct links, and built-in sharing options like WhatsApp or SMS. Avoid extra steps, logins, or permission requests that could interrupt the flow.
2. Use clear, valuable incentives: Give rewards to both the person sending the invite and the person receiving it. Offer discounts or access to premium features and avoid rewards with unclear value.
3. Add natural sharing triggers: Let users share their achievements, scores, or progress. Prompt sharing after moments of achievement, like completing a level or reaching a milestone.
4. Improve the app experience: Ensure the app is stable, fast, and easy to navigate. Users are more likely to recommend an app that works well and provides real value.
5. Test and optimize: Run A/B tests on invite messages, referral timing, and design. Track what improves invite rates and conversions, and adjust based on results.
6. Focus on high-performing user segments: Use your K-factor data to identify users, regions, or channels with higher referral activity or conversion rates. Prioritize these segments in your acquisition and engagement efforts.
7. Continue to work on ASO: Improve your app store listing to increase the likelihood that invitees will install the app. Use clear screenshots, concise descriptions, high-quality icons, and updated keywords. Strong ASO increases referral conversion rates, which helps raise your K-factor.
8. Keep the app updated: Release new features, content, or improvements regularly. Updates give users a reason to return and to share the app with others.
9. Show social proof: Display reviews, download numbers, or in-app activity from other users. Visible signs of engagement can help build trust and encourage sharing.

As a mobile measurement partner (MMP), Adjust provides the infrastructure to measure and optimize the referral flows that influence K-factor—specifically, how many users send invites and how many of those invites convert. With Adjust Measure, marketers can attribute installs from referral links and gather referral data via attribution callbacks. This enables accurate reward delivery to the referrer and helps identify users who drive new growth. Rewards can also be triggered based on post-install events, such as sign-up or purchase, allowing teams to align incentives with meaningful engagement.

Deep linking with Adjust’s TrueLink ensures that referred users are directed to the correct in-app destination, even across platforms or if the app isn’t installed (deferred deep linking). TrueLink also supports contextual deep links, which allow marketers to brand and personalize links for improved user experiences. These capabilities reduce friction, improve conversion, and give marketers full control over the referral experience at link-level. TrueLink links can be branded, localized, and used across channels (all-purpose links) to support scalable and measurable acquisition.

Ready to see how Adjust can grow your app business? Request a demo today.