When the first Bitcoin block was mined in January 2009, there was only one (1) transaction in the block. This block is known as the Genesis block or block 0.
Bitcoin blocks in the past have a technical design of a maximum of one (1) megabyte in size, and this has a direct correlation to the number of transactions it can potentially store.
This article analyses several blocks in the blockchain and shows you the maximum and the minimum number of transactions a single block can hold. If you want to analyse the bitcoin blockchain on your own, we have written an article on it.
Maximum Number of Transactions in one Block
Bitcoin Core developers increased the block size limit through the Segregated Witness (SegWit) protocol upgrade in 2017. SegWit is introduced to increase the block size while accommodating more transactions in a single block.
So what is the maximum size a single bitcoin block can hold?
After the SegWit upgrade, Bitcoins blocks now have a theoretical limit of 4 megabytes. However, from our observations of several blocks on the blockchain, realistically speaking, most blocks are about 2 megabytes or less.
Below is a screen of an actual block that is almost 1.7 megabytes in size.
Minimum Number of Transactions in one Block
Our blockchain data analysis observed that the minimum number of transactions per block lies in the usage. There are times when transactions are constantly high in the range of 1500 to 3000, but there are also times when it was low, less than 100 transactions per block.
It all lies in the actual Bitcoin transaction usage at that point in time, if more or fewer people are performing transactions.
Below is a screenshot of a block storing only 54 transactions. The block size is also significantly smaller than the larger blocks with more transactions.
According to the Bitcoin whitepaper;
“A block header with no transactions would be about 80 bytes“Bitcoin whitepaper – page 4
The bitcoin block size correlates to the number of transactions. Based on our observations from several bitcoin blocks, the more transactions a single block hold, the larger the block size it becomes. This is logical as it now has to store more transactions data.
Segwit implementation in 2017 increased the block size intending to store more transactions. This facilitates more transactions to be confirmed every 10 minutes or so. From our blockchain data observations, the current maximum number of transactions can theoretically go higher than 3,500 in a single bitcoin block.
If you are interested to learn more about the basics of Bitcoin, the following articles may be helpful to you;