
By comparison, Bitcoin transaction speeds are tremendously lower. Currently, the block size is set 1MB (1,048,576 bytes — although through SegWit, that size. allowing for a traditional 1MB block with no Extra size through to a larger block containing solely Segwit transactions. The practical maximum size for a block. The Bitcoin Core protocol limits blocks to 1 MB in size. Each block contains at most some 4,000 transactions. Blocks are added to the blockchain on average every.