IPv4 Subnet Calculator
Enter an IPv4 address in CIDR notation to calculate network address, broadcast, host range, subnet mask, and more.
Binary representation
Subnet Splitter
| # | Network | First Host | Last Host | Broadcast |
|---|---|---|---|---|
| 1 | 192.168.1.0/26 | 192.168.1.1 | 192.168.1.62 | 192.168.1.63 |
| 2 | 192.168.1.64/26 | 192.168.1.65 | 192.168.1.126 | 192.168.1.127 |
| 3 | 192.168.1.128/26 | 192.168.1.129 | 192.168.1.190 | 192.168.1.191 |
| 4 | 192.168.1.192/26 | 192.168.1.193 | 192.168.1.254 | 192.168.1.255 |
About the IPv4 Subnet Calculator
This tool calculates all key properties of an IPv4 subnet from CIDR (Classless Inter-Domain Routing) notation — the standard format for specifying an IP address and its network prefix length (e.g., 192.168.1.0/24). Enter any valid IPv4 CIDR and instantly get the network address, broadcast address, first and last usable host, subnet mask, wildcard mask, total hosts, and usable host count.
CIDR notation replaced the older class-based addressing system (Class A/B/C) and is used universally in modern networking: router configurations, cloud VPC setup (AWS, GCP, Azure), firewall rules, and Kubernetes network policies all use CIDR ranges. A /24 gives 254 usable hosts; a /27 gives 30; a /30 gives 2 (point-to-point links). The subnet splitter shows how to divide a larger network into equal-sized subnets.
All calculations run locally in your browser using pure JavaScript bitwise arithmetic. No IP addresses are sent to any server.
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation expresses an IP address and its network prefix as address/prefix, e.g., 192.168.1.0/24. The prefix length (0–32) specifies how many bits are fixed for the network — the remaining bits identify individual hosts within that network.
What is the difference between network address and broadcast address?
The network address is the first address in a subnet (all host bits set to 0) and identifies the subnet itself — it cannot be assigned to a host. The broadcast address is the last address (all host bits set to 1) and is used to send packets to all hosts in the subnet simultaneously. Neither is usable for individual hosts.
How many hosts can a /24 subnet hold?
A /24 subnet has 256 total addresses (2⁸), with 254 usable hosts — the network address and broadcast address are reserved. Common subnet sizes: /30 = 2 hosts, /29 = 6, /28 = 14, /27 = 30, /26 = 62, /25 = 126, /24 = 254, /23 = 510, /22 = 1022.
What is a wildcard mask?
A wildcard mask is the bitwise inverse of the subnet mask. Where the subnet mask has 1s (network bits), the wildcard mask has 0s, and vice versa. Wildcard masks are used in Cisco ACLs and OSPF configurations to match a range of IP addresses.
What are private IP address ranges?
RFC 1918 defines three private address ranges not routable on the public internet: 10.0.0.0/8 (Class A, 16M hosts), 172.16.0.0/12 (Class B-equivalent, 1M hosts), and 192.168.0.0/16 (Class C-equivalent, 65K hosts). These are used in home networks, corporate LANs, and cloud VPCs with NAT for internet access.