CIDR Calculator
Enter an IPv4 address and CIDR prefix to expand it into the network address, broadcast, usable host range, subnet mask, wildcard, and total address count. Runs in your browser.
- Network
- 192.168.1.0
- Broadcast
- 192.168.1.255
- Subnet mask
- 255.255.255.0
- First host
- 192.168.1.1
- Last host
- 192.168.1.254
- Wildcard
- 0.0.0.255
- Usable hosts
- 254
- Total addresses
- 256
What CIDR notation means
CIDR (Classless Inter-Domain Routing) writes a network as an address plus a prefix length, like 10.0.0.0/16. The number after the slash is how many leading bits belong to the network. A /16 fixes 16 bits and leaves 16 for hosts, which is 65,536 addresses. It replaced the old class A/B/C system, so any prefix from /0 to /32 is valid, not just /8, /16, and /24.
Want every prefix at a glance? The subnet mask cheat sheet lists all 33 in one table. Setting up remote access into the subnet? WireGuard vs OpenVPN covers the VPN side.