# How to calculate total / max electricity consumpton for a server / or hardware equipment.?

Consider I have in the cisco 2911-sec/k9 data sheet with following power values

Maximum Power with AC Power Supply (Watts) 210

With this given value how can one calculate total electricity produced or consumed?

I want to use this figure to find out total billing cost?

The data sheet for the particular switch have following values for power specifications.

``````AC Input Voltage
AC Input Frequency
AC Input Current Range AC Power Supply (Maximum)
AC Input Surge Current
Typical Power (No Modules) (Watts)
Maximum Power with AC Power Supply (Watts)
``````

I want to know what value I should be using for my calculation to find maximum power requirements?

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To estimate the cost of power consumption you need to add up the estimated usage of all of the components. Here is a good blog post with some rough numbers. Items like the power supply rating and input voltage aren't a huge factor in estimating consumption. Its the usage of the actual components that matter.

However actual consumption of power will vary greatly with actual usage (ie CD-ROM doesn't draw a lot of power if not reading a disc). To accurately measure consumption you need to get a device like the Kill-a-Watt to measure the actual watts drawn from the outlet.

If you use a power reader you need to convert the watts to kilowatt-hours (because that is how electricity is billed). Jeff at CodingHorror has a good writeup of this The Cost of Leaving your PC On.

``````watts * (8760 hrs per yr) / 1000 = kilowatt-hours
``````

Then multiple that by your electricity cost to get the yearly total

``````kilowatt-hours * cost per hour = yearly cost
``````

You can then divide that by month or day.

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Thank you for reply. I understood how to calculate the total bill by your formulas, but what I'm initially interested in is which figures or value or parameters give me the total watts consumed or its consumption captivity, I'm talking about theoretical one, just a rough calculation. – iloveyouga Apr 12 '13 at 14:02
Also in the last formula why you divided it by 1oo (cost per hour / 100)? – iloveyouga Apr 12 '13 at 14:04
@iloveyouga updated answer with info about estimating. The /100 was copied from the blog post where he had the cost as 14.28 cents which should be \$0.1428 hence the /100. I've removed it from my answer since I just have cost per hour. – Brad Patton Apr 12 '13 at 14:14
thank you Brad:). My friend said you can calculate power consumption through this watts =ac current (in amps) x input voltage. Would this actually do? – iloveyouga Apr 12 '13 at 14:25
@iloveyouga that is the correct formula for watts and you could probably use the PSU number to get max consumption. The problem is that the PC power usage varies quite a bit and unless you are running it 100% all the time it will not be accurate. – Brad Patton Apr 12 '13 at 14:32