Calculating Power Consumption of a Server Rack

Calculating Power Consumption of a Server Rack

Power Consumption of Server Rack:

Power consumption of server rack is the overall power that each server carries and to determine how much power is consumed per rack and each server in the rack.

How to calculate the overall power


First, you need to know the useable square footage of your facility and the Power for each Server (Server Watts). You will also need to find out your Facility Voltage (VAC), which will likely be 120V or 240V. Next, you need to determine the Number of Racks and the number of Servers Per Rack.



  1. R= Total number of racks used for the server.
  2. S=Total number of servers.
  3. S/R = How many numbers of server can be stack on the rack.
  4. Ws= Power consumption of server in watts, each server has different power consumption. So, power consumption of each and every server.
  5. VAC= Input voltage as per country standard.
  6. kW= Converting the power consumption watts to kilo watts.

Calculating the power per server 


Collect the data for each server power consumptions in watts(W) and convert it to kilo Watts(kW).
Note: Server power consumption per will varies depending upon the power supply in it, some of the servers has one power supply and some servers have two.

Formula to change watts to kilo watts. 
kW= W/1000

Hence, consumption of each server power watts is divided by 1000 to convert it into kilo watts.

  1. Calculate Maximum kW Per Rack
  2. To begin to calculate your Maximum kW per rack, you will first need to use the Number of racks you already determined, or you can calculate Maximum will be using.
  3. Taking the usable floor space for the data center and dividing it by the amount of floor space each rack takes up, which will depend on your aisle arrangement. On a standard 8-pitch layout, that’s 16 ft2.
  4. Next, determine the power supply of each server (Server Watts), which will be used to calculate the kilowatts per Server. This number is usually found written on the power supply of the server. Next, divide the number of server watts by 1,000 to get kW pr server.
  5. After calculating the kW per server, you will then multiply that by the number of servers per rack, to get your final data center Maximum kW per server.

kW=W/1000xNumber of servers per rack.



Calculate Total Kilowatts
To calculate Total kilowatts needed, you want to multiply the number of servers per rack by kW per server.
Use this number to calculate the Watts per ft^2.

Calculate Total Watts Per Square Foot
Finally, you need to calculate your Total watts per square foot. This is how much power your data center consumes per square foot. To get your Total watts per ft^2 you will need to multiply the Total Kilowatts you calculated before and multiply it by 1,000. You will then divide that by the usable square footage of the facility (usually the amount of raised floor space). The result will be your Total watts per ft^2.


    • Related Articles

    • Initial Troubleshooting Steps When Server Power Socket Is Getting Yellow Light/Red Light.

      Power Socket Power Socket is the point on server where the power cable is plugged in. These sockets are part of the server's power supply unit (PSU) and are essential for delivering electrical power to the server. Server with different colored lights ...

    • Powering NVIDIA L40S GPUs in ASUS ESC8000A-E12P Servers

      Powering NVIDIA L40S GPUs in ASUS ESC8000A-E12P Servers Overview When deploying NVIDIA L40S GPUs in ASUS ESC8000A-E12P servers, users may encounter a power connector mismatch issue. This KB article explains the root cause and provides the official ...

    • Asus GPU Server ESC8000A-E12 Failing to Power On

      Asus GPU Servers Failing to Power On During the assembly process, several Asus GPU servers failed to power on. The issue was identified during initial hardware setup and pre-deployment verification. Further investigation is required to determine ...

    • Configuring BMC in ASUS Server

      To configure the Baseboard Management Controller (BMC) IP address on an ASUS server, initially access the server's BIOS/UEFI settings and then configure the BMC network settings. Here's a step-by-step instructions Server BMC Configuration preparation ...

    • PSU Error Alert - Troubleshooting Guide

      Purpose This document provides a standardized approach for handling and troubleshooting the PSU Error alert, ensuring quick identification of power supply issues and maintaining system power redundancy. Alert Name PSU Error Alert Description This ...