Consulting firm and integrator Astadia joined the crowd this week with its version of a popular marketing tool, an online return on investment (ROI) calculator for customers interested in cloud computing. It's based on empirical results from Astadia's string of cloud customers and purports to show what a company might save by moving applications and infrastructure out of their basement and on to Force.com.

Astadia makes some bold claims, such as assuming an 80% reduction in network costs and 50% savings in storage costs and data center spending. However, in a nod to the complicated reality of IT spending, Astadia's calculator lets users adjust their expected level of savings if they wish. The company said it's a thumbnail view of the potential of cloud. Is it really that easy for an enterprise to figure out cloud costs?

"Different organizations with different workloads, architectures, cost structures, and usage demand profiles will need to use the cloud in different ways," said Joe Weinman, VP of global strategy and product development for AT&T and prominent author on economic theory in the cloud market.

Weinman's theories and logical proofs have been instrumental in validating the long-term vision of cloud computing and he's even built his own cloud calculators, which can be safely described as the most comprehensive and rigorous economic modeling tools for cloud by a long margin.

Weinman said that by now every CIO should be taking cloud into account when they plan spending, and they probably are: Most recent surveys indicate high levels of awareness on cloud and moderate levels of adoption, mostly in the more mature Software-as-a-Service (SaaS) segment. That's only natural, said Weinman, since CIOs should be carefully balancing clear advantages of cloud service, like business agility and elastic spending, with existing IT operations. He said that evangelists should be taken with a grain of salt, as cloud will not replace the enterprise data center immediately, but so should detractors, who pooh-pooh the public services model.

"The correct answer is somewhere in the middle: cloud computing is an important option in the CIO's toolbox, offering potential immediate cost savings as well as strategic benefits," said Weinman. But every IT department is going to have to find a different balance of inside versus outside to maximize their ROI.

Calculating cloud in context

That means all the cloud calculators out there need to be taken in context; the curious should make sure they understand the premise of each one, as well as the assumptions they are based on.

Astadia is perfectly up front about this. Astadia vice president Cory Vander Jagt said that the company bases projected savings levels on the use of Force.com, rather than a generalized assumption on using Platform-as-a-Service (PaaS), because that's where Astadia has the most experience and therefore the most data. He also said Astadia's customers are doing online sales and marketing applications. That's seen as a classic use for cloud computing, and something Force.com specializes in. If you wanted to use Amazon Web Services (AWS) or Azure, you would not see the same kinds of savings.

"This has been verified by three or four independent research projects by now -- we see four or five times faster development on Force.com," Vander Jagt said.