Opportunistic routing (OR) is a promising technology for improving the throughput of wireless networks. In contrast to traditional routing techniques that forward messages along predetermined paths, OR schemes allow selection of a set of candidate nodes as potential next-hop forwarders to utilize the broadcast nature of the wireless medium. An analysis of transmission latency and signaling overhead depend on the number of hops required to transmit a packet from source to destination. In this paper, we propose three models to analyze the number of transmissions for successfully delivering a packet with three OR schemes: single-forwarder OR with known topologies, multiple-forwarder OR with known topologies, and multiple forwarder OR with unknown topologies. These models are useful in the network planning. The simulation results verified the accuracy and usability of the three models.