It is from the day you activate your subscription. So, if you did that today, in 30 days you would get charged again, and receive your Crown allotment.
The monthly rotation starts when ESO+ is activated.
You'll get an email indicating the activation date, and the reminder of the automatic billing cycle. You'll also be told Crowns have been applied to your account.
Depending on the platform you're playing, head to the subscription management system to determine when the next billing date is, which auto-renews unless you disable/cancel.
If you do cancel, the sub remains active until the end of that cycle.
There is no prorated amount or refund of unused sub.
It's 30 days from the day you start it, nothing to do with calendar months.
Which means it would run from the 14th December - 13th January, because there's 31 days in December.
I think it actually goes exactly to the hour/minute you activated it, but I've never checked exactly. I know there's been times when I've gotten a 30 day subscription and on the 30th day I have ESO+ in the morning and not in the evening.
Edited by Danikat on December 14, 2021 2:58PM
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"Remember in this game we call life that no one said it's fair"
I think it actually goes exactly to the hour/minute you activated it, but I've never checked exactly. I know there's been times when I've gotten a 30 day subscription and on the 30th day I have ESO+ in the morning and not in the evening.
I think it does, because the day mine renews I don't receive the crowns until around the same time in the afternoon every time.