Blockchain technology has been rapidly spreading around the world, as different business competitors have been racing to adopt this new technology in various economic sectors. We can simply define blockchain as a distributed ledger or a record book with data shared between the participants in a network. The first and most famous application of a blockchain is Bitcoin, which is a P2P electronic cash system developed by Satoshi Nakamoto in 2008. This technology has gained attention for its characteristics such as decentralization, stability, security, and immutability. To achieve these characteristics, blockchain relays on its consensus algorithm. Since 2008, many consensus algorithms have been developed to meet the different requirements of various blockchain-based applications in different economic sectors. These algorithms determine the efficiency and security of a blockchain as well as preventing double-spending and Byzantine Generals Problem. Moreover, there have been several studies that evaluated different consensus algorithms. This study presents an empirical comparison between two of the most common consensus algorithms, Proof of Work (PoW) and Proof of Stake (PoS). This comparison considers time taken to reach a consensus (T consensus) in the network by each algorithm and fork rate as main performance metrics while manipulating system parameters such as number of nodes, block generation interval and block size. To the best of our knowledge this is the first empirical study to evaluate and compare the performance of different consensus algorithm in a blockchain network. Eventually, this study will serve as a guide to help implement the suitable consensus algorithm for a blockchain network.