> For the complete documentation index, see [llms.txt](https://docs.glesys.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.glesys.com/products/compute/kvm-virtual-machines/how-tos/resize-virtual-machines.md).
# Resize virtual machines
***
Resizing a KVM VM changes the resources (CPU, RAM, and disk) allocated to the virtual machine. These are the two resizing options for KVM virtual machines:
* **CPU and memory**. This option increases or decreases the number of CPU cores and the amount of RAM available to a VM.
* **Storage**. You can permanently increase the disk size of a virtual machine.
Increasing a virtual machine’s memory and CPU improves its performance. Increasing the size of its disk increases the amount of data that can be stored.
## **Resize a KVM VM using the control panel**
In the server overview, you can reconfigure the server's resources, such as the number of CPU cores, memory, and disk size.
Click on the VM name in the control panel, then **Edit configuration**.
You drag the handles in the *Reconfigure* dialog box to adjust the CPU cores, RAM, and disk size. Click **Reconfigure** to save; the changes take effect immediately, and you can utilize all resources in a few seconds.
### **Reconfigure CPU and memory**
Memory can be increased without requiring a server reboot. However, if you decrease the memory, the server will automatically restart.
Using Linux as the operating system allows for increasing or decreasing CPU cores without rebooting the virtual machine. In contrast, Windows requires a restart when the number of CPU cores is changed.
### **Reconfigure storage**
Note that **you can only increase the disk size**. Once it has been increased, it cannot be reduced again. When resizing the disk, the virtual machine will restart automatically, as disk changes cannot be made while the machine is running. The system partition will automatically expand to the new size during the reboot.
### Overview of the monthly costs
You can always view a breakdown of the costs for your KVM virtual machine at the bottom of the server's overview page. It's a good idea to check the cost overview after making changes to the VM to avoid any surprises.
## **Resize a KVM VM using the API**
To resize a VM using the [API](/platform/control-panel/api.md), use the [server/edit](https://github.com/GleSYS/API-docs/wiki/API-Documentation#serveredit) endpoint. To view the costs of a VM, use the [server/costs](https://github.com/GleSYS/API-docs/wiki/API-Documentation#servercosts) endpoint. To view the estimated costs, use the [server/estimatedcost](https://github.com/GleSYS/API-docs/wiki/API-Documentation#serverestimatedcost) endpoint.
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