IPv4 vs IPv6: Detail Explained
The world is quickly running out of IPv4 addresses, and a new version of the internet protocol, IPv6,…
Subnet Calculator
Enter an IP address and CIDR prefix length below to instantly calculate all subnet details — subnet mask, network address, broadcast address, usable host range, and total hosts.
/ 24
Common Subnet Reference Table
Quick reference for the most commonly used CIDR prefixes in networking:
| CIDR | Subnet Mask | Usable Hosts | Common Use |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 | Large ISP, Class A networks |
| /16 | 255.255.0.0 | 65,534 | Large enterprise networks |
| /24 | 255.255.255.0 | 254 | Most common — home & office LAN |
| /25 | 255.255.255.128 | 126 | Medium-sized LAN segment |
| /26 | 255.255.255.192 | 62 | Small office segment |
| /27 | 255.255.255.224 | 30 | Small department/VLAN |
| /28 | 255.255.255.240 | 14 | Small branch office |
| /29 | 255.255.255.248 | 6 | Point-to-point WAN link |
| /30 | 255.255.255.252 | 2 | Router-to-router link |
| /31 | 255.255.255.254 | 2 | Point-to-point (RFC 3021) |
| /32 | 255.255.255.255 | 1 | Host route / loopback |
How to Use This Subnet Calculator
Using our free subnet calculator is simple. Enter your IP address in the first field (e.g., 192.168.1.0), then set your CIDR prefix length using the input field or slider (e.g., /24), and click Calculate. The tool instantly shows you all subnet details.
What is Subnetting?
Subnetting is the process of dividing a large IP network into smaller, more manageable sub-networks (subnets). It improves network performance, enhances security by isolating network segments, and makes IP address management more efficient. Every network engineer needs to understand subnetting — it is a core skill tested in the CCNA, Network+, and other networking certifications.
Understanding CIDR Notation
CIDR (Classless Inter-Domain Routing) notation represents an IP address and its associated network prefix. For example, 192.168.1.0/24 means the first 24 bits are the network portion, leaving 8 bits for host addresses — giving you 254 usable hosts. The higher the CIDR number, the smaller the subnet.
Key Subnet Terms Explained
- Network Address: The first address in a subnet — identifies the subnet itself. Cannot be assigned to a host.
- Subnet Mask: A 32-bit number that separates the network and host portions of an IP address.
- Broadcast Address: The last address in a subnet — used to send data to all hosts. Cannot be assigned to a host.
- Usable Hosts: Total addresses minus 2 (network + broadcast). These are the addresses you can assign to devices.
- Wildcard Mask: The inverse of the subnet mask — commonly used in Cisco ACLs and OSPF configuration.
Frequently Asked Questions
What is a /24 subnet?
A /24 subnet has a subnet mask of 255.255.255.0 and provides 254 usable host addresses. It is the most common subnet used in home and small office networks.
How many hosts can a /24 subnet support?
A /24 subnet supports 254 usable host addresses (256 total addresses minus network and broadcast addresses).
What is the difference between a subnet mask and a wildcard mask?
A subnet mask uses 1s to represent the network portion and 0s for the host portion. A wildcard mask is the exact inverse — 0s for the network portion and 1s for the host portion. Wildcard masks are used in Cisco router ACLs and OSPF area definitions.
Can I subnet a /32 address?
No. A /32 is a host route — it represents a single IP address with no subnet. It is used for loopback addresses and specific host routes in routing tables.
