# Viral coefficient

Viral coefficient is the number of new users each existing user brings into a product through referrals. It is the same measure as K-factor: a value of 1 or more means every user replaces themselves, so growth continues without new outside traffic.

Canonical page: https://getlaunchlist.com/glossary/viral-coefficient. Updated 2026-10-15.

## What the number tells you

A viral coefficient answers one question: when one person joins, how many more does that bring? It is a ratio, not a total, which is why it says more about a referral program than a raw signup count does. A list can grow fast because you posted in the right place on the right day while its referrals do almost nothing.

| Viral coefficient | What it means for your list |
| --- | --- |
| 0 | Nobody who joins brings anyone in. Every signup is one you found yourself. |
| Between 0 and 1 | Referrals multiply your own effort, then fade out. Growth still depends on you finding new people. |
| Exactly 1 | Each person replaces themselves. The list keeps growing at a steady pace from referrals. |
| Above 1 | Each round of referrals is larger than the one before, so the list compounds while the rate holds. |

## The same measure as K-factor

Viral coefficient and K-factor are two names for one calculation: the share of users who refer, multiplied by the average number of successful referrals per referrer. The formula, a worked waitlist example and a table of what each value does to your final list size are on the [K-factor](https://getlaunchlist.com/glossary/k-factor) page, so they are not repeated here.

## It measures reach, not speed

A viral coefficient says nothing about time. Two lists at 0.8 grow very differently if one turns a signup into a referred friend within a day and the other takes six weeks. When you compare yourself across periods, keep an eye on how quickly referrals arrive after a signup as well as how many arrive. A shorter cycle often matters as much as a higher coefficient, especially when your launch date is fixed.

## Reading it without fooling yourself

- **Divide by real signups.** Count referrals against confirmed signups, or at least against signups that passed your spam checks. Bots and throwaway inboxes inflate both sides of the ratio and leave you with a number that describes nobody.
- **Look at it by period.** An all-time figure hides a loop that worked in week one and stopped in week four.
- **Separate a spike from a loop.** One person with a large audience can refer hundreds of people in a day. That lifts the coefficient, but it is a single event, not a loop that repeats.
- **Check what the incentive attracts.** If a reward goes up and the coefficient follows, look at whether the new referrals confirm and stick around. [Milestone rewards](https://getlaunchlist.com/glossary/milestone-rewards) tied to the product tend to bring in people who want it.

## Viral coefficient in LaunchList

The Referrals tab in [Analytics](https://getlaunchlist.com/features/analytics) states your viral coefficient in words: for every 100 confirmed signups, how many arrived through a referral. At 1.00 or higher it says your list keeps growing from referrals alone. Below that it says referrals add to your growth while other channels still carry it. Referrals that fail the fraud checks never count, so they never reach this number.

The loop that produces the number is described on the [viral loop](https://getlaunchlist.com/glossary/viral-loop) page.

Further reading: [the K-factor and viral coefficient guide](https://getlaunchlist.com/blog/viral-coefficient-k-factor-guide).

## Frequently asked questions

### Is viral coefficient the same as K-factor?

Yes. Both names describe the number of new users each existing user brings in through referrals, and both are calculated the same way. Some teams use viral coefficient for a projected figure and K-factor for a measured one, but the arithmetic does not change.

### What does a viral coefficient of 1 mean?

It means each user brings in, on average, exactly one more. Every group of new signups replaces itself, so the list keeps growing from referrals even if you stop driving traffic, for as long as the rate holds.

### Is a viral coefficient below 1 bad?

No. It means referrals add to your growth rather than carry it. A viral coefficient of 0.5 still turns every 100 signups you bring in into roughly 200 by the time the referrals stop, so it lowers the cost of every signup you find yourself.

### How do I increase my viral coefficient?

Give more people a reason to share and give sharers a reason to keep going. Asking right after signup, one-tap sharing, a place in line that moves when a friend joins, and a ladder of rewards all help. Prizes that attract people who only want to win raise the number without raising the quality of your list.

## Related terms

- [K-factor](https://getlaunchlist.com/glossary/k-factor.md)
- [Viral loop](https://getlaunchlist.com/glossary/viral-loop.md)
- [Milestone rewards](https://getlaunchlist.com/glossary/milestone-rewards.md)