Below is a link to 10 different IP video storage and network bandwidth calculators. A humorous story told by many IP security industry pundits is, if you use 10 different calculators all with the same variables, you will get 11 different answers. Try it and see for yourself and of course start of with the SecurityHive.com calculator.
DNF IP-Camera Storage Calculator
http://www.dnfsecurity.com/calculator/
Stardot Bandwidth and Storage Calculator
http://www.stardot.com/bandwidth-and-storage-calculator
Panasonic/Video-Insight Storage and Bandwidth Calculator
https://www.security.us.panasonic.com/storage-and-bandwidth-calculator
Tyco Exacq Configuration Calculator
https://exacq.com/config/
Milestone Storage Calculator (MPEG4)
https://www.milestonesys.com/support/let-us-help-you/presales-support/Storage-Calculator/
Vicon IP Video Storage and Bandwidth Calculator
Axis Design Tool (bandwidth and storage needs)
https://www.axis.com/en-us/learning/web-articles/technical-guide-to-network-video/bandwidth-considerations
Moxa IP CCTV bandwidth and storage calculator
http://www.moxa.com/Event/Net/2012/IP_CCTV_Calculator/index.htm