How is my storage calculated?

Storage is driven by how many measurements you persist:

devices × tags-per-message × messages-per-day × days-retained

So a slower publish interval, fewer tags, or shorter retention all reduce storage. A device reporting 5 tags once a minute generates far less than one reporting 20 tags every second.

Your plan's max_storage caps the total; the Quota & limits page shows usage. To keep more history without growing storage, stream to an egress integration.