The grid below illustrates the comparison between cumulative costs over time between Office 365 (cloud solution) and on-premise Exchange. In this example, we have assumed 15 users- 5 with unlimited mailboxes at $8 per user per month, 10 with 50GB mailboxes at $4 per user per month, and cloud mailbox backup for each user at $1.50 per month.
If you opt for on-premise Exchange, your cumulative cost over eight years with software assurance (entitling you to free upgrades) is $6,760- a 31% savings off of the cloud solution. Even if you do not purchase software assurance- say you purchase one Exchange upgrade outright during the eight-year period- the cumulative cost is $4,018, which is a 59% savings off of the cloud solution.
If you are interested in seeing this comparison with real-life numbers as they apply to your business, please email firstname.lastname@example.org.