Substack Referral Calculator
Enter your subscribers and an estimated referral rate to see how much a referral cascade could add, wave by wave. Free, no signup.
Plan your referral cascade
| Wave | New from referrals | Running total |
|---|---|---|
| 1 | 25 | 525 |
| 2 | 1 | 526 |
| 3 | 0 | 526 |
| 4 | 0 | 526 |
| 5 | 0 | 526 |
Each wave assumes the referral rate applies again to the subscribers gained in the previous wave - a simplified cascade model, not a guarantee. Real referral behavior fades faster than this unless each wave is actively prompted (e.g. a referral program or a "share this" callout).
How the referral cascade is modeled
Each wave applies your referral rate to the subscribers gained in the previous wave, not to your original total - so growth naturally tapers off rather than compounding forever. At a 5% rate, wave one adds 5% of your current subscribers, wave two adds 5% of *those* new subscribers, and so on, converging to a finite total rather than growing without bound.
This models what happens if referral behavior repeats on its own, which real referrals rarely do without a prompt. A referral program, a direct ask, or a visible incentive typically needs to re-trigger each wave - it doesn't happen automatically just because someone subscribed.
Questions
What's a realistic referral rate to use?
It depends heavily on whether you actively prompt for referrals (a program, an incentive, a direct ask) versus hoping it happens organically - organic referral rates are typically low single digits or less.
Why does the subscriber growth taper off across waves?
Each wave's referral rate applies only to the subscribers gained in the wave before it, not your full audience - so at rates under 100%, each wave is smaller than the last and the total converges rather than growing forever.
Does this account for a referral program with rewards?
Not directly - it models a constant referral rate per wave. A real referral program with escalating rewards would need a higher assumed rate to reflect the extra incentive.
How do I find my most likely referrers?
NotesIQ's Top Fans tab ranks the readers who restack and comment on you the most - the people most likely to actively refer others, rather than guessing who might.