Wireless sensor network consists of numerous small and low cost sensors which collect and transmit environmental data. These nodes are spatially distributed and capable of measuring their ambient. Sensor node is responsible for collecting data in regular intervals, converting the obtained data into electronic signals and transmitting data to sink node or base station through reliable wireless communications. Moreover, these nodes are supplied by non-rechargeable batteries with limited energy. Lifetime and network coverage are crucial factors in WSNs. Thus, particular algorithms must be employed so that energy consumption is reduced. In this paper two clustering algorithms LEACH and HEED are investigated.