VM Storage Calculator (beta)

This tool calculates required storage capacity for a vSphere ESX cluster based on the planned VM workload.

Virtual server / VM specification:

Disk (GB): 
RAM (GB): 
# of VMs: 
Disk (GB): 
RAM (GB): 
# of VMs: 
Disk (GB): 
RAM (GB): 
# of VMs: 
Disk (GB): 
RAM (GB): 
# of VMs: 
Disk (GB): 
RAM (GB): 
# of VMs: 
Allocate space for VM swap files
Misc. configuration and log files, per VM (GB):
Allocation for VM snapshots (%):
# of ESX hosts:
Storage for ESX installation (GB):
Storage over-subscription (a.k.a. thin provisioning) (%):
Allocation for grows (%):

VM workload:
Total provisioned disk space (GB):2000
Total configured memory (GB):320
Total number of VMs:30
Average VM configuration: 
  - Disk space (GB):66.6667
  - Memory (GB):10.6667
Number of hosts:3
Storage: (GB)(%)
Total provisioned VM disk space:2000
Used VM disk space:1333.333344.77
Over-subscribed capacity:666.6667
Allocation for VM snapshots:40013.43
Allocation for VM swap files:32010.74
Allocation for VM conf. & logs:7.50000.25
Total VM storage:2060.833369.19
Total ESX disk space:240.81
Allocation for grows:893.500030.00
Total storage required:2978.3333100


Virtual server / VM specification:
Disk - disk capacity allocated to a VM (provisioned storage).
RAM - memory capacity allocated to a VM. We use this value to calculate disk space required for swap files. If you are planning to use memory reservation only for a specific set of VMs, reduce the value accordingly.

Allocate space for VM swap files - specifies whether or not VM swap space will be included in the calculation. This setting applies to all VM configurations, regardless of the RAM values.

Misc. configuration and log files, per VM - defines how much space will be allocated for VM log and configuration files (excluding swap file).

Allocation for VM snapshots - specifies how much of additional storage capacity will be allocated for VM snapshots; calculated as percentage of the provisioned VM storage.

Storage for ESX installation - storage required for hypervisor (ESX) installation and operations.

Storage over-subscription - if you are planning to use thin provisioning enter the expected level of over-subscription; 0% means no thin provisioning and over-subscription.


The values in the right-most column are calculated as a percentage of the total required storage value.

Total provisioned VM disk space - the sum of all VM provisioned disk capacity (total provisioned VM storage).

Expected Used VM disk space - the value is derived from the Total provisioned VM disk space value for the given Storage over-subscription percentage.

Over-subscribed capacity - calculated as the difference between the Total provisioned VM disk space and the Used VM disk space values.

The Get Link button generates a URL for this page with all currently entered data and then shortens it using the Google URL Shortener service If you save or bookmark the short link, you can return to your calculation at a later time.

Note that, as stated by Google, "All URLs and click analytics are public and can be accessed by anyone" - so use at your discretion.

This tool is a beta version and we welcome your feedback.
This tool does not take into account compression and deduplication.
The default parameters used by this tool are for illustration purpose only. Please adjust as required.

See also:
vSphere ESXi Server Virtualization Calculator