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Capacity

Capacity Planner

How many VMs fit on a host while balancing cost and performance? Set your ESXi capacity and VM classes, choose a mix, and read planned consumption across the allocation, reservation and utilisation models. Aim for 90 to 110%.

Binding constraint
101%
Allocation CPU is the limit
VMs in this mix
12VMs
136 vCPU · 544 GB vRAM
Fits before 100%
11.9VMs
this mix, scaled to full capacity
5-yr savings vs public
$68,000
private cloud vs public, per host

ESXi host capacity

The physical host. Usable capacity removes hypervisor overhead; reservation is capped at base clock.

Threads (HT)128threads
Usable CPU (utilisation)114threads
Max CPU reservation150GHz
Usable memory704GB

Classes of service

Overcommit ratios per class. CPU and memory each have their own; Bronze is the densest.

CPU overcommit (vCPU : thread)
Memory overcommit (vs DRAM)
Gold allocation capacity114 vCPU · 704 GB
Silver allocation capacity228 vCPU · 845 GB
Bronze allocation capacity342 vCPU · 986 GB

VM sizing

One representative VM per class. Gold is 4× Bronze, Silver 2×. Utilisation and reservation are set per class.

Gold VM16 vCPU · 64 GB
Silver VM8 vCPU · 32 GB
Bronze VM4 vCPU · 16 GB

VM mix

How many of each class on this host. The six numbers below are planned consumption; aim for 90 to 110% on the binding one.

Number of VMs
ModelCPUMemory
Allocation101%73%
Reservation95%65%
Utilisation72%75%

You run out of capacity when any number reaches 100%. Green is 90 to 110%; amber is headroom; red is over capacity.

Cost comparison

Public cloud has no class of service: every VM is priced the same. Private cloud cost is per host over five years.

Capacity reserved for HA (1 of hosts)10%
Public cloud annual (this mix)$46,648
Public cloud over 5 years$233,240
Private cloud over 5 years / host$165,000
Savings with private cloud$68,000

Interactive version of the Capacity Planning worksheet from the guide. Defaults reproduce it; change any green field to model your estate.