Subscriber lifetime calculator
Drop in a subscriber export and see how long people really stay: the survival curve, median lifetime, and how many are still with you after 30, 90, 180 and 365 days. Your file never leaves your browser.
Drop CSV files here, or choose them
Needs a signup date and an unsubscribe date (blank for people still subscribed). If your platform exports subscribed and unsubscribed people as separate files — Mailchimp does — add both.
Read by your browser and processed on your device. Nothing is uploaded — close the tab and it’s gone.
Read the guide
How long do your subscribers really stay?
Averaging how long departed subscribers lasted makes your list look fickle. Survival analysis counts everyone, including the people still here.
Built into Carrier Crow
The same Kaplan–Meier analysis runs on your live list as the Subscriber Lifetime report — no exports, next to attrition, growth against churn, and reports you build yourself.
See the reporting →