Calculating your viral coefficient (k) is straightforward once you know the Viral Coefficient formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Viral Coefficient Calculator.
What is Viral Coefficient?
The Viral Coefficient calculation tells you your viral coefficient (k) from a few simple inputs. The figure you are solving for here is the viral coefficient (k).
The Viral Coefficient formula
The core formula is:
Viral coefficient (k) = Invites sent per user × Invite conversion rate ÷ 100Here is what each input means:
- Invites sent per user — a number. Example: 5.
- Invite conversion rate — a percentage, such as an annual rate. Example: 2%.
How to calculate it step by step
- Write down the invites sent per user (for example, 5).
- Write down the invite conversion rate (for example, 2%).
- Apply the formula above to get your viral coefficient (k).
- Double-check the result with the Viral Coefficient Calculator.
Worked examples
Example 1
| Input / Output | Value |
|---|---|
| Invites sent per user | 5 |
| Invite conversion rate | 2% |
| Viral coefficient (k) | 1.00 |
With invites sent per user of 5 and invite conversion rate of 2%, the viral coefficient (k) works out to 1.00.
Example 2
With invites sent per user of 10 and invite conversion rate of 2%, the viral coefficient (k) works out to 2.00.
| Result | Value |
|---|---|
| Viral coefficient (k) | 2.00 |
Example 3
With invites sent per user of 2.5 and invite conversion rate of 2%, the viral coefficient (k) works out to 0.50.
| Result | Value |
|---|---|
| Viral coefficient (k) | 0.50 |
Tips for an accurate result
- Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
- Round only at the very end. Rounding inputs early can shift the final answer noticeably.
- Re-run the numbers whenever an input changes, rather than estimating from an old result.
Prefer not to do the maths by hand? — the Viral Coefficient Calculator does it instantly, for free, with the formula and a worked example built in.
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