How to use the subscriber list growth rate calculator
An SMS or email subscriber list is never a number that only goes up. You can add thousands of opt-ins in a month and still end up flat once unsubscribes, spam complaints and hard-bounce removals are taken out. Enter your starting count, new opt-ins and removals, and this calculator shows net new subscribers alongside the growth rate.
Growth rate is not a retention ratio. Dividing the ending count by the starting count gives a figure near 100%. This calculator uses (end − start) ÷ start, so a flat list reads 0% and a shrinking list reads negative.
The unsubscribe rate divides removals by the starting count. If you are paying to acquire opt-ins while that rate climbs, send frequency or content is the usual cause. Enter the period length and you also get net new subscribers per day, which makes a 30-day month and a two-week campaign window comparable. Target growth varies far too much by industry and list size for this tool to suggest a benchmark.
Frequently asked questions
New opt-ins count everyone who joined during the period. Net new subtracts unsubscribes and removals from that figure. Judge acquisition campaigns on opt-ins, but judge the health of the list on net new.
It depends on list size, industry and how much you spend on acquisition, so there is no single benchmark worth quoting. Compare the same list against its previous period, or the weeks before and after a campaign.