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Email list growth calculator

How many subscribers will you get? Enter your traffic, sign-up rate and unsubscribe rate to see your list grow month by month, and compare a standard form with a gamified pop-up.

The form is pre-filled with example numbers so you can see how it works. Replace them with your own.

Your website

For example the share of visitors who are shown your pop-up or scroll down to your form.

Sign-up rate of the offer

Example values, not benchmarks. Replace both with the rates from your own forms, pop-ups or tests.

Your list

Unsubscribes, bounces and removed contacts per month as a share of the list. Your email platform's reports show it.

Value of a subscriber (optional)

For example the revenue an average subscriber brings in. Leave it empty to skip.

Result

Standard formGamified pop-upDifference
New sign-ups per month
List size after 12 months
Net growth
Lost to unsubscribes

List size month by month

  • Standard form
  • Gamified pop-up
MonthStandard formGamified pop-up

How it is calculated

  • New sign-ups per month = monthly visitors × share who see the offer × sign-up rate
  • list(m) = list(m−1) × (1 − churn) + new sign-ups, where list(0) is your current list size and churn is the monthly unsubscribe rate
  • Each month, the unsubscribe rate is taken off last month's list, then that month's new sign-ups are added
  • Lost to unsubscribes = the sum of list(m−1) × churn over all months
  • Value of the list = list size × value per subscriber per month (a yearly value is divided by 12)
  • Value over the whole period = the sum of each month's list size × value per subscriber per month
  • Numbers are rounded to whole subscribers when shown. The calculation keeps the decimals.

The calculator runs in your browser and nothing you type is sent to us. It assumes the same traffic, sign-up rate and unsubscribe rate every month, so treat the result as an estimate, not a forecast.

How to work out how many subscribers you will get

Three numbers decide how fast an email list grows: how many people visit your website, how many of them see your sign-up offer, and how many of those sign up. Multiply them and you have your new sign-ups per month. With 20,000 monthly visitors, a pop-up shown to 60% of them and a sign-up rate of 2%, you get 20,000 × 0.6 × 0.02 = 240 new subscribers a month.

The share who see the offer is easy to overlook. A form in the footer is only seen by people who scroll to the bottom of the page. A pop-up is seen by everyone it is shown to. Raising that share can matter as much as improving the form itself.

Why the list does not just add up

Every month some people leave the list. They unsubscribe, their address starts to bounce, or you remove them because they never open your emails. The monthly unsubscribe rate (often called churn) is taken off the list before the new sign-ups are added:

list(m) = list(m−1) × (1 − churn) + new sign-ups

This is why a large list grows more slowly than a small one with the same number of sign-ups: it loses more people each month. Over time the list moves towards a level where the people who leave match the people who join. That level is new sign-ups ÷ churn. With 240 sign-ups a month and 1% churn it is 24,000 subscribers. Find your real churn in the reports of your email platform.

Compare two sign-up rates

The calculator works out two scenarios side by side, one for a standard sign-up form and one for a gamified pop-up, such as a spin the wheel or a scratch card that people play to win a prize. The pre-filled rates are only examples. Sign-up rates depend on your audience, your offer, the prize and where the form sits, so use the rates from your own forms or run a test. Our guide to growing your email list with gamification has 12 tactics to try, and our list of email pop-up ideas has examples of offers that give people a reason to sign up.

Keep the new subscribers

A bigger list is only worth something if people stay on it and read your emails. Ask only for the details you need: see how many fields a sign-up form should have. Decide whether to confirm new addresses with double opt-in. It gives you a cleaner list, at the cost of some sign-ups that are never confirmed.

From subscribers to value

If you know roughly what a subscriber is worth, for example the revenue an average subscriber brings in per month or per year, add it to see the value of the list. To check whether a single campaign pays for itself, use our campaign ROI calculator. And if you want to collect sign-ups with games, prizes and consent built in, see how Scratcher helps you collect sign-ups.

The calculator gives an estimate based on the numbers you enter. Real traffic and sign-up rates change from month to month.

Questions

Questions about growing an email list

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  • Yes. It is free to use as often as you like, and you don't need an account. Nothing you type is sent to us.

  • Multiply your monthly visitors by the share who see your sign-up offer and by the offer's sign-up rate. Then take off the people who unsubscribe each month. The calculator does both and shows the list month by month.

  • Use the rate from your own forms or pop-ups if you have it. You find it in your website or email platform as sign-ups divided by the number of people who saw the form. The pre-filled rates are only examples, not averages.

  • It depends on how often you send, what you send and how people joined the list, so we don't give a number. Look at the last few months in your email platform: people who unsubscribed, bounced or were removed, divided by the list size.

  • Because the number of people who leave grows with the list. When the list reaches new sign-ups ÷ churn, the people who leave each month match the people who join. To grow beyond that, get more people to see the offer, raise the sign-up rate or lower the churn.