Block size depending on transaction count It's widely known that Bitcoin has a limit of 1 MB per block.

However, the average block size is currently about 0.6 MB:



(original data)

According to this thread, Bitcoin transactions has an average size of 512 B. For the sake of simplicity, I'm not considering the 80 B of block header.

Given that, it's possible to fit about 1200 transactions in a block today. Considering that a new block will be mined every 10 minutes, the current capacity of the network is 2 tps:

1200 transactions/block / 10 min/block / 60 sec/min = 2 transactions/s


This seems like a very low throughput, specially when compared to Paypal's average rate of ~115tps and Visa's average rate of ~2000 tps.

Now imagine that I want to build a side chain that can handle as much traffic as Visa network. I want to mantain most of the parameters of the Bitcoin's blockchain (10 min/block, ~512 B/transaction), but being able to process 2000 tps.

In this case, my block size would be the following:

2000 transaction/s * 512 B/transaction * 60 s/min * 10 min/block = 586 MB/block


Is the estimate above correct, or am I missing something?

If it's correct, what are the impacts of switching from a 1 MB block size to 586 MB?
Is the estimate above correct, or am I missing something?


Your estimations seem (more or less) fine.


  If it's correct, what are the impacts of switching from a 1 MiB block size to 586 MiB?


The two major ones I see are:


large blocks make full nodes more difficult/expensive to operate (i.e. requires better specs and better upload/download speeds); thus bad for decentralization as not many people will be able to run a full node
the blocks will take longer to propagate through the network, thus it increases the chances of orphan blocks and double spends.


For a more detailed list see here.

Note, that these concerns/drawbacks for an increased block size were raised for a 4, 8 or 32MBs increase... a 586MB increase would be way too excessive. And if you keep the parameters similar to bitcoin you would have the same issues in the side chain.