One of the common questions from our clients is determining how many Ampere their equipment needs, and how they can calculate their average usage.

Considering the following electrical factors:

  • Current (amps)
  • Voltage (volts)
  • Electrical power (watts)

amps * volts = watts

This formula determines the energy a piece of your network equipment uses at a moment. However, before colocating your servers and appliances, we recommend you to calculate how many Amps your system will draw.

Below is a simple example of how you can calculate the power. The first step is to calculate the total maximum power draw in kWatts, then from the mentioned formula, you can find out how many Amps your system will draw.

Let say you need a 10U space with the following specification:


1 router with the maximum power draw of 100 Watts

1 switch has a maximum power draw of 50 Watts

8 Server with  200 Watts

Total Watts = 100 + 50 + (200*10) = 1950 W

Amp = Watt (2150) / Volt (120)

Amp 18 A


Though the formula shows you need 18 amp for this set up in your rack, but this is for maximum use and not all the time your servers and routers are on max use. So, you will need to find the average watts you use.


Besides the unexpected higher usage on the start time, the average usage is under your expected load. A server that can draw 200 watts with 120v power, might draw up to 1.6 amps, but it can go down to 1 amp under typical usage.

If you are not sure which colocation plan is fitted to your need, just give us a call and talk to one our data center experts, they will give you more details about your options and even can customize a plan to your colocation requests.