CIDR Calculator
Read an address/prefix and show the network it belongs to.
Same arithmetic as the subnet calculator, from a single address/prefix field.
Network
10.0.0.0
Broadcast
10.0.3.255
First host
10.0.0.1
Last host
10.0.3.254
Usable hosts
1,022
Mask
255.255.252.0
Calculations happen in your browser.
Worked example
10.0.0.8/22 belongs to the network 10.0.0.0. The broadcast is 10.0.3.255, the mask is 255.255.252.0, and there are 1,022 usable hosts.
FAQ
- How do I type a CIDR?
- Address, a slash, then the prefix, such as 10.0.0.8/22.
- What is the difference between this and the subnet calculator?
- This page takes the address and prefix in one field. The subnet calculator takes them separately. The arithmetic is the same.
- Can the address be any host in the block?
- Yes. The network address is calculated from the prefix, so the host bits you type don’t change the network.