Drop out rate question

Someone asked me if there was a way to determine what our membership dropout rate was. Has anyone figured out how to calculate this on a year to year basis?

Stripe gives you some metrics in its dashboard: https://dashboard.stripe.com/billing

And here are analytics services for payment gateways. Probably one of those would help you with what you want. https://www.google.com/search?q=analytics%20stripe%20paypal