Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Projected list size
27,420
Net subscribers added
15,420
Net growth this month
1,328
Months to reach target
32
Steady-state list ceiling at this pace
233,333
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter current list size.
- 2Enter new signups per month.
- 3Enter monthly churn rate (%).
- 4Enter months to project.
- 5Enter target list size.
- 6Read your projected list size on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Every list leaks. Unsubscribes plus hard bounces plus quiet disengagement typically clear 0.3–0.8% a month, so gross signups always overstate the growth you keep.
Worked example
Using the values the calculator loads with:
Inputs
- Current list size: 12000
- New signups per month: 1400
- Monthly churn rate: 0.6 %
- Months to project: 12
- Target list size: 50000
Results
- Projected list size: 27,420.49
- Net subscribers added: 15,420.49
- Net growth this month: 1,328
- Months to reach target: 32
- Steady-state list ceiling at this pace: 233,333.33
What each field means
Inputs
- Current list size
- The current list size used in the calculation. Starts at 12000 so you have a working example on load.
- New signups per month
- The new signups per month used in the calculation. Starts at 1400 so you have a working example on load.
- Monthly churn rate (%)
- The monthly churn rate used in the calculation, measured in %. Starts at 0.6 % so you have a working example on load. Accepted range: 0–20 %.
- Months to project
- The months to project used in the calculation. Starts at 12 so you have a working example on load. Accepted range: 1–60.
- Target list size
- The target list size used in the calculation. Starts at 50000 so you have a working example on load.
Results
- Projected list size
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net subscribers added
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Net growth this month
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Months to reach target
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Steady-state list ceiling at this pace
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the email list growth calculator work?
Every list leaks. Unsubscribes plus hard bounces plus quiet disengagement typically clear 0.3–0.8% a month, so gross signups always overstate the growth you keep. The underlying maths is: Net monthly = Signups − (List × churn rate); projected forward month by month.
What do I need to enter?
5 values: current list size, new signups per month, monthly churn rate, months to project, and target list size. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the projected list size result mean?
It is returned as a whole number and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Email List Growth Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/email-list-growth
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/email-list-growth" target="_blank" rel="noopener">Email List Growth Calculator — RevenueLab</a> (2026).</p>
Source: [Email List Growth Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/email-list-growth) (2026).