To calculate Viral Coefficient (VC), you use this formula:

Viral Coefficient = (Number of Invites per User) × (Conversion Rate)

In your case:

Total active users = 190

Referrals = 4

Converted referrals = 2

Step 1: Find Invites per User
This is:

Number of Referrals / Total Active Users
= 4 / 190 ≈ 0.02105

Step 2: Find Conversion Rate
Converted / Total Referrals
= 2 / 4 = 0.5

Step 3: Multiply
VC = 0.02105 × 0.5 ≈ 0.0105