Subnet Calculator
Calculate network address, broadcast address, subnet mask, number of hosts, and CIDR notation for any IPv4 or IPv6 subnet.
Subnet Calculation Results
Network Information
Host Information
IPv6 Subnet Details
Subnet calculator basics
CIDR notation combines an IP address and prefix length, such as 192.0.2.0/24. The prefix defines which bits are the network portion and which bits are available for hosts.
Key fields in the result
- Network address: the first address in the subnet.
- Broadcast address: the last IPv4 address in the subnet.
- Usable host range: addresses normally assigned to hosts, excluding network and broadcast for typical IPv4 subnets.
- Subnet mask: dotted-decimal representation of the IPv4 prefix.
Practical examples
A /24 IPv4 subnet has 256 addresses, commonly 254 usable hosts. A /26 has 64 addresses, commonly 62 usable hosts. A /30 is often used for point-to-point links with two usable IPv4 addresses.
Common mistakes
Do not mix host addresses and network addresses when documenting firewall rules. For IPv6, there is no broadcast address, and subnet planning usually uses larger boundaries such as /64.
Related tools
Use IPv6 Tools, IP Geolocation, and Ping Test when troubleshooting address allocation and reachability.
Quick Reference
This tool helps with common network administration tasks. Run the check above and review the results. For detailed troubleshooting, see the related tools below.