Viral Coefficient Calculator
Calculate your K-factor to predict referral-driven growth.
K-FACTOR
1.00
Viral — self-sustaining
K = invites per user × conversion rate. A K above 1 means each user brings more than one new user — self-sustaining growth.
What is Viral Coefficient?
The viral coefficient, or K-factor, measures how many new users each existing user brings in through referrals. A K above 1 means growth is self-sustaining and compounds on its own.
K = invites per user × invite conversion rate
How to read your result
- K > 1 means every user brings more than one new user — true viral growth.
- K between 0 and 1 still lowers CAC, just without runaway growth.
- Small gains in invites or conversion move K a lot.
- Sustained K > 1 is rare — treat it as a stretch goal, not a plan.
Frequently asked questions
What is a good viral coefficient?
Any K above 1 produces self-sustaining, compounding growth. Most products land below 1, where referrals still meaningfully reduce acquisition cost.