How is firebase realtime database storage calculated

Question

I am curious how is firebase storage calculated. If I stored x GB data, then remove it later, how will this calculated ? Is is calculated once a month, or maybe something like

Answer 1

Great question. Sorry for the delay, but I had to get the answer from one of our billing experts.

Firebase tracks the database size during the month and determines the weighted average of the size for billing.

So if you had 29 days where you had 1GB and 1 day where you had 2GB, the average is 29/30*1 + 1/30*2 = 0.967 + 0.067 = 1.033 GB.