IP Subnet Calculator
Enter an IP address with a subnet mask (e.g. 192.168.1.0/24 or 255.255.255.0) to instantly calculate network details including network address, broadcast address, usable host range, wildcard mask, and total hosts.
Subnet Calculator
How to Use This Subnet Calculator
- Enter an IP address in the IP Address field (e.g.
192.168.10.0) - Enter either the CIDR prefix (e.g.
24) or the Subnet Mask (e.g.255.255.255.0) — both fields sync automatically - Click Calculate to see full subnet details
- Scroll down to the Subnet Division section to split the network into equal subnets
10.0.0.0/8) and the tool will parse both automatically.
CIDR Quick Reference Table
Common subnet masks and their corresponding CIDR prefix, total hosts, and usable hosts:
| CIDR | Subnet Mask | Wildcard Mask | Total Hosts | Usable Hosts |
|---|
What is Subnetting?
Subnetting is the process of dividing a large IP network into smaller, more manageable sub-networks (subnets). It allows network administrators to improve performance, enhance security, and make efficient use of IP address space.
Understanding CIDR Notation
CIDR (Classless Inter-Domain Routing) notation expresses an IP address and its associated subnet mask as a single value. The number after the slash (/) indicates how many bits are used for the network portion of the address.
For example, 192.168.1.0/24 means the first 24 bits are the network address, leaving 8 bits for host addressing — giving 256 total addresses and 254 usable hosts.
Key Terms Explained
- Network Address
- The first address in a subnet, used to identify the network itself. It cannot be assigned to a host.
- Broadcast Address
- The last address in a subnet, used to send data to all devices on the network. It cannot be assigned to a host.
- Wildcard Mask
- The inverse of the subnet mask. Commonly used in Cisco ACLs and OSPF configurations.
- Usable Hosts
- Total hosts minus 2 (network and broadcast addresses). These are the IPs that can be assigned to devices.