A virtual central processing unit, virtual processor, or vCPU is a physical CPU assigned to a virtual machine (VM).

Typically, VMs only have access to one vCPU; however, in a cloud environment, they can have more vCPUs. Adding more vCPUs depends on the number of CPU cores and the number of timeslots, which are periods of times the hypervisor has access to the host machine’s physical hardware, across all the available cores.

A shared virtual central processing unit, or shared vCPU, is a physical CPU that is assigned to multiple VMs, all of which share the physical CPU through organized time slots.