Marketing · Free tool
Email List Growth Calculator
An email list grows by what you add and shrinks by what you lose, and the losses compound quietly. This email list growth calculator shows where your list will stand after each of the next six months, for marketers and founders deciding whether a signup push or a churn fix matters more.
- OutputList size for six months
- No sign-up
- Copy or print the result
- How it works ↓
Your entries stay in this browser. Use Fill example to see a finished page first.
What this marketing tool gives you
The output leads with the month 6 list size, then a six-row table of list size per month. It is a quick way to show in a meeting that, at a given churn rate, adding subscribers alone flattens out. Your entries remain on your own computer, and nobody needs an account to use it.
What you enter
- Starting list: the number of subscribers today
- Monthly new subscribers: how many join each month
- Monthly churn rate: the percent of the list lost each month (0 to 100)
Worked example
With the example values, a starting list of 1,000, 200 new subscribers a month and 10% monthly churn: month 1 = 1,000 × 0.9 + 200 = 1,100. The list then grows to 1,190, 1,271, 1,343.9 and 1,409.51, ending at 1,468.56 in month 6.
How is email list growth projected?
Each month, the list keeps (1 − churn rate) of the previous month's size, then adds the monthly new subscribers. In formula form: next month = previous month × (1 − churn ÷ 100) + new subscribers. The tool repeats this six times and rounds each month to two decimals.
Churn is applied to the list before the new subscribers are added, so new joiners are not churned in the month they join. The churn rate must be between 0 and 100, and the other inputs cannot be negative.
Tips before you use the result
- Churn here means everyone who leaves the list: unsubscribes, hard bounces and addresses you remove in cleanups.
- At a steady churn rate, the list approaches new subscribers ÷ churn rate. At 200 a month and 10% churn, that ceiling is 2,000.
- Run it twice, once with more signups and once with lower churn, to see which lever moves month 6 more.
- Round the projection to whole subscribers when you present it; the decimals are a result of the percent, not real people.
Frequently asked questions
How do I forecast email list growth?
Take the current list, subtract the share you expect to lose each month, and add the new subscribers you expect to gain. Repeat for each month. This calculator does exactly that for six months using one churn rate and one monthly signup figure, and shows each month's size in a table.
What churn rate should I use?
Use your own history if you have it: people lost in a month divided by the list size at the start of that month. Include unsubscribes, bounces and removals. The tool accepts any rate from 0 to 100 percent and applies the same rate every month.
Why does my list stop growing even though I add subscribers every month?
Because churn scales with list size while new signups stay fixed. Eventually the monthly loss equals the monthly gain. In the tool's model, that balance point is new subscribers divided by the churn rate as a decimal, so reducing churn raises the ceiling.
Can I project more than six months?
No. The calculator always shows six months. For a longer view, take the month 6 figure as the new starting list and run it again, which continues the same month-by-month logic for another six months. Keep the same churn rate and signups unless you expect them to change.
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Results depend on the figures you enter; check them against your own records before you rely on them. Last updated: October 2026 · Kurums editorial team.