Blockchain, introduced in bitcoin system is disrupting the way transactions are done in businesses via charging small transaction fees. It is observed that the acceptance of blocks in the blockchain is based on transaction value. Transmittals through blockchain are favoured due to low transaction cost and grander security. However, attempt of implementing blockchain to revolutionise business processes writhes from problem of waiting time for blocks. In this paper, the transaction-confirmation-time is appraised using queuing theory, where the approval rate of blocks in blockchain is concocted using Markov queue model. Four specific use cases of 1, 3, 6 and 60 confirmations are considered for practical purposes.