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Calcimator

Network Rack Space Calculator

Calculate rack units needed from equipment list including switches, routers, servers, UPS, and patch panels. Includes power and cooling estimates.

Inputs

RU
RU
RU
RU
RU
RU

Results

Total Equipment RU

32 RU

Racks Needed

1

Estimated Power

3.65 kW

≈ 4 microwaves

Rack Utilization76.2 %
Spare RU10 RU
Heat Output12,454 BTU/hr
Cooling Required1.04 tons
Estimated Weight960 lbs
How to Use This Calculator
  1. Enter Number of Switches, Switch Size, and Number of Routers.
  2. Set Router Size, Number of Firewalls, and Firewall Size.
  3. Adjust Number of Servers, Server Size as needed.
  4. Review Total Equipment RU, Racks Needed, and Estimated Power (kW).
  5. Use Rack Utilization (%) and Spare RU to inform your decision.

How the result changes with Number of Servers

Number of ServersTotal Equipment RURacks NeededEstimated Power
1044 RU26.65 kW
3594 RU319.15 kW
65154 RU534.15 kW
90204 RU746.65 kW

What each input means

Number of Switches
Total network switches
Switch Size
Rack units per switch (1U or 2U typical)
Number of Routers
Total routers/L3 devices
Router Size
Rack units per router
Number of Firewalls
Total firewalls/security appliances
Firewall Size
Rack units per firewall
Number of Servers
Total rack-mount servers
Server Size
Rack units per server (1U or 2U common)
UPS Units
Uninterruptible power supply units
UPS Size
Rack units per UPS (3-6 RU typical)
Patch Panels
Number of patch panels (copper + fiber)
Cable Management Panels
Horizontal cable management panels (1U each)
Rack Size
Total rack units per rack (42U standard, 48U tall)

How this is calculated

Formula

Total RU = Σ(Count × RU/Device); Racks = ⌈Total RU / Usable RU⌉

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Number of Switches = 6, Switch Size = 1, Number of Routers = 2, Router Size = 2 = 13 input(s) provided
  2. Calculate Total Equipment RU
    Total Equipment RU
    32 = 32
  3. Calculate Racks Needed
    Racks Needed
    1 = 1
  4. Calculate Estimated Power
    Estimated Power
    3.65 = 3.65
  5. Calculate Rack Utilization
    Rack Utilization
    76.2 = 76.2
  6. Calculate Spare RU
    Spare RU = max(spareRu
    10 = 10

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators.

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