Bitcoin Forum

I'm lost in this topic. I was thinking the max blocksize for bitcoin was 1Mb but if we see the last confirmed transactions they are bigger than that. just like this one:

https://www.blockchain.com/btc/block/00000000000000000000320ce3487360f83e24ca033dc0e6bb7a692549373c72
Size 1,362,748 bytes

So, what did i miss? can some one explain to me how big is the max block size please?

One of the things SegWit has introduced is an "increase of capacity". The witness data is not counted in the 1MB.
Reading this may help: https://medium.com/@jimmysong/understanding-segwit-block-size-fd901b87c9d4

Max block size of bitcoin was always 1MB or 1,000,000 bytes but with the introduction of segwit they are no longer taken into consideration but rather the block is limited to 4MB weight units. You should have a read on the stackexchange topic to understand the difference between a virtual size and a normal size :Is there a difference between bytes and virtual bytes (vbytes)? (https://bitcoin.stackexchange.com/questions/89385/is-there-a-difference-between-bytes-and-virtual-bytes-vbytes)

The size of a block should never exceed 1,000,000 virtual bytes with each virtual byte equals to 4 weight units. Hence, a block should never exceed 4,000,000 weight units. In the above mentioned transaction the total weight of the block was 3,993,079 weight units which is slightly lesser than 4 million weight units. When there was legacy transactions taking place, virtual bytes was similar to normal bytes but in the case of segwit they are two different entities to be taken into consideration.

Thanks for your answers NeuroticFish and seoincorporation, it was a really interesting article to read, and the answer is SegWit. That was what I miss...

Now I understand the weight units, so, thanks again guys, I will read more about the topic.

Plus you should read the history and the long difficult path/drama of how Segwit was activated, and how the community forced the miners to hear them, https://bitcoinmagazine.com/articles/long-road-segwit-how-bitcoins-biggest-protocol-upgrade-became-reality

It forces you to question, "Who truly secures the network?"

OP, there are also trolls who would misinform people like you, and say FUD like "Segwit transactions are anyone-can-spend transactions, and miners can steal users' funds".

They are simply NOT true. Know the facts, and the FAQ, https://segwit.org/faq/home

Although I miss those trolls. I miss the long threads, trolling them back with the truth. Haha.

Ahhh good old SegWit. The implementation that Bitcoin Cash advocates didn't want and instead increased their block size to 8MB. In the meantime they increased it again to 32MB and another fork suggested 128 MB, if I am not mistaken.
The witness data can occupy up to 60% percent of a block size but with Segwit this data is omitted from the main blocks. 

Yes, i know the fork on BCH was to increase the block size, but i didn't know BCH avoid segwit. I used to think the bigger blocks was a nice solution to avoid the network getting stuck with unconfirmed transactions, but that solution in the long run only would bring a crazy heavy blockchain.

Thanks for the info guys.

you are wrong. BCH was created to make money just like majority of other altcoin.
and the owners/creators have no problem with SegWit otherwise they would have removed "all" of it from their source code instead of only a tiny part of it. BCash currently supports BIP-173 (Base32 address format for native v0-16 witness outputs) and the most important part of BIP-143 (Transaction Signature Verification for Version 0 Witness Program). the only thing that it doesn't do is moving signatures to "witness" and have the witness scriptpubs!

Then you should research about Schnorr Signature and Taproot as well.

P.S. if you're satisfied with the answer and don't have any question related to the main topic (block size), consider lock the tread.


Theorically it's almost 75%, even though it requires transaction where it's signature is very big (very rare). Besides, i wouldn't say the signature part is omitted from "main" block since it's only moved to witness space on block and signature is very important part of transaction/block.

Transaction's signature or witness part only committed/removed if your client/wallet doesn't support SegWit.

Hahaha. Like me, you also learned, the hard way.

Bandwidth, for low latency, is a limited resource than what the big blockers care to admit in my opinion. I believe they have already understood this fact, but will never admit it.