Use these design tools to assist you in sizing your network:
•
Cisco CallManager Capacity Tool (CCMCT)
http://www.cisco.com/cgi-bin/CT/CCMCT/ct.cgi 
The Cisco CallManager Capacity Tool calculates the minimum number of active subscribers that are required to support a given installation. The inputs consist primarily of quantity and usage information on the various device types that are supported in a Cisco CallManager system.
•IPC Voice Tools
http://tools.cisco.com/partner/ipccal/index.htm
The IPC Voice Tools, such as the IPC Resource Calculators, are intended to simplify and automate the process of sizing IP Contact Center (IPCC) resources that are required for specific IPCC business operations. They are also useful for verifying and troubleshooting existing installations.
The output from these tools can also be used as input to the IPCC Express Configuration Tool and the CallManager Capacity Tool.
•Solution Expert tool
Solution Expert is a web-based tool that assists in the design, configuration, quoting, and ordering of Unified Communications products. Solution Expert is available for Cisco sales and partner systems engineers who have Unified Communications specializations.
With the Solution Expert tool, users can generate a recommended solution based on their requirements. Users can modify the recommended configuration if desired. Solution Expert validates any changes when it presents the new solution. Solution Expert also generates a bill of materials with list pricing, a Visio diagram, and other design documentation. To access Solution Expert, go to the following URL. For an overview of how to use the tool, see the introductory PDF on the home page.