I saw an external runtime that is 1.5 tetrabytes. But I have no clue how big that is.

I found this on the internet:

1,024 megabytes = 1 gigabyte

1,024 gigabytes = 1 terabyte

1,048,576 (1,0242) megabytes = 1 terabyte

But I can't get my brain around those numbers.

I currently have a 250 gig external drive and it's full! I was going to get another one that is 500 gigs, but I looked at my partitioned drive and a couple of my smaller 40 gig external drives and I don't think it would all fit onto 500 gigs. So I want something bigger, and a tetrabyte seems bigger.

How many 250 gigs are in 1.5 tetrabytes.  Knowing that will help me to visualize the size.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi