Why the block height do not correspod to bitcoin core database size?

[supermankid]

Hello all,

If current block height is ~731378
And as I understand it bitcoin block is 1 MB
731378 blocks = 731378 MB
731378/1024 ~714 GB
But the current up-to-date block is about 500 GB.
How did this size difference possible?
Or
Where am I getting it wrong?

[nc50lc]

Blocks can be lower than the "maximum" block size (currently 4 million Weight Units).
Most of the first thousands blocks are empty and the rest (until Bitcoin became famous) only have a small number of transactions included,
so their size are only a few kB.

For example: Block #1000 doesn't have any transaction in it aside from the coinbase txn; its size is only 0.216 kB.

[ABCbits]

Blocks can be lower than the "maximum" block size (currently 4 Weight Units).

To be more precise, maximum block size was 1MB before SegWit activation (August 2017) and now it's 4 million weight units (some people also refer it as 4 kWu).

Most of the first thousands blocks are empty and the rest (until Bitcoin became famous) only have a small number of transactions included,
so their size are only a few kB.

Or rather few hundred bytes.

[nc50lc]

Blocks can be lower than the "maximum" block size (currently 4 Weight Units).

To be more precise, maximum block size was 1MB before SegWit activation (August 2017) and now it's 4 million weight units (some people also refer it as 4 kWu).

Thanks, I previously edited it from "4 vMB" because I decided to use "Weight Unit" instead but forgot to add "million".