The Bitcoin mempool are broadcasted Bitcoin network transactions that have not been added to a block. Awaiting transactions in mempool are usually chosen for addition into the freshly mined block according to their transaction fee. However, when the transaction fee is low, it may take longer time for the confirmation of such transaction.
In recent weeks, there was a considerable spike in the backlog of unconfirmed transactions on Bitcoin network thereby making the Bitcoin mempool reach its biggest size in over two years. Likewise, block mining and confirmation of transactions are taking longer time.
The reduction in Bitcoin mining activity that followed the third halving event could be the reason for the huge increase in unconfirmed transactions on the network. Bitcoin mining activity is reducing due to miners’ drop off the network, thereby increasing the time to mine a block and it is slowing down the network.
At the moment, the 7-day average value for the mempool size is at its highest (67.87 megabytes) since after Bitcoin price reached its lifetime high in January 2018. The mempool size is now double in under a week.
Blockchain.com noted a rise in the average time for a transaction to be added to a block from about 7 minutes to 16 minutes. BitInfoCharts said it takes an average of 10 minutes to mine blocks in recent times while the typical time is 10 minutes.
The difficulty involved in finding a new block changes according to the hash rate value while Bitcoin network is capable of accommodating a changing hash rate. However, the difficulty level is updated every fortnight.
The average transaction fee for Bitcoin is currently $6.64 (ten times more than it was this time in April) due to the rise in block space competition. Likewise, this value is remarkably close to its two-year high.