Subnet
Expand an IPv4 CIDR block into its network address, broadcast, usable host range and total count.
Runs in your browser — nothing you type here is sent anywhere.
IPv4 CIDR block
network10.0.0.0/22
netmask255.255.252.0
wildcard0.0.3.255
first host10.0.0.1
last host10.0.3.254
broadcast10.0.3.255
usable hosts1,022
total addresses1,024
Subnet arithmetic is a small amount of bit manipulation that nobody enjoys doing twice. Given `10.0.0.0/22` you want the first and last usable address, the mask, and how many hosts fit — quickly, and without an error that only shows up when two ranges overlap in production.
It shows the mask in both dotted-decimal and prefix form, the network and broadcast addresses, the usable range, and the host count, so you can lay out a VPC or check whether two blocks collide.
What people open it for
- Planning non-overlapping subnets for a VPC or private network
- Checking whether a firewall rule covers the range you think it does
- Converting between /24-style prefixes and subnet masks
In the terminal
cidr 10.0.0.0/22
Every utility is also a command in the desktop's shell.