Virtualisation Calculations






How we Calculated Your Results

Thank you for using the Abtec Virtualisation RoI Calculator, I hope you found it useful. We’ve done our best to make the calculations in the tool as realistic as possible. As the tool requires just a few simple inputs from you, we’ve used some assumptions in creating the output.

For a more realistic evaluation of whether virtualisation is right for you please ring 01858 438 548, and our engineers will be able to take you through a much more realistic return on investment calculator.

Data Sources and Calculations

There are a number of calculations that take place in the tool; here’s where we got the data.

Virtual Server Ratio

We’ve used a conversion ratio of one virtualised server to nine physical servers. Depending on the workload of your existing physical server environment this may be too conservative.  We’ve delivered virtualisation projects successfully with a 1:18, and more, ratio; but we think that the 1:9 ratio is appropriate for the sake of the calculator.

Power and Cooling

One of the largest costs in having a server is powering it, and then removing the heat that it produces to ensure that it runs well.  We estimated the cost of electricity at 12.5 pence per KWH (Kilowatt Hour).  Our range of costs were between 10 and 15 pence, due to the volatility in the electricity supply market.

Server Energy Use

There are few independent studies available that investigate how much energy a server uses, both directly in power and indirectly in heat extraction.  Of the studies available, the strongest figure, without heat extraction is 3741 KW per year.  This would be a 427W server running 24/7.  One of the benefits of virtualisation is that you don’t have to have all of the servers running 24/7.  Your virtualisation software can shift applications to one physical server and power down the rest of the servers when the organisation isn’t busy; such as a weekend.


We couldn’t find any studies on the costs of heat extraction, I guess this could be to do with the highly variable size and environment of the server room.  Our accredited virtualisation engineers have a rough rule of thumb, which is that it will be double the cost of running the server.

This would make the annual cost of running a server 24/7 to be £1403.

Maintenance Fees

We’ve multiplied the number of servers that you’ve input by the the cost of maintenance that you entered.

Staff Management

This is the internal cost of resource for maintaining the servers.  A high number here could mean that the IT team aren’t working as effectively as they could.  Virtualization reduces the number of physical servers, and the time spent maintaining them.  The cost was worked out by taking the mean average hourly pay for an IT support technician (£10), and multiplying it by the number of your hours you stated you work on each server per year.

Server Refresh

This is the calculated cost of refreshing your server infrastructure.  We’ve estimated that each server has a lifespan of six years.  We’ve taken away the number of servers that you’ve indicated are less than two years old, from the overall number of servers.  Then we have divided this number four (for the remaining four years of the server lifespan). Finally, we’ve multiplied this number by £4000, which represents the cost of an average server.

Got that?…Phew.

Virtualisation Installation Costs

This is the project cost of installing the new vitualized environment. This cost includes the servers, software, SAN and engineering time; everything that you need for fo a successfull virtualization project.  It doesn’t include the costs of the licences for the applications (such as SQL, MS Exchange etc), as this depends on what applications you want to run.

We’ve estimated the costs of the the project this way – £10,000 for each new server plus £30,000 for the SAN, licences, engineering time, training and everything else.  So, for two new servers there would be an overall cost of £50,000.  Again, this is probably over egging the costs, but it hopefully gives you a good idea.

Want to Know More About Virtualisation?

Give us a ring on 01858 438 548 to find out how virtualisation can benefit you.