Subnet Calculator
Calculate subnet details from any IP address and CIDR prefix. Get network address, broadcast, host range, and total hosts instantly.
Common Subnet Sizes
| CIDR | Subnet Mask | Total Addresses | Usable Hosts |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 |
| /16 | 255.255.0.0 | 65,536 | 65,534 |
| /24 | 255.255.255.0 | 256 | 254 |
| /28 | 255.255.255.240 | 16 | 14 |
| /30 | 255.255.255.252 | 4 | 2 |
| /32 | 255.255.255.255 | 1 | 0 |
How to Use
- 1 Enter an IP address in dotted-decimal notation, e.g. 192.168.1.0
- 2 Enter the CIDR prefix length (0–32), e.g. 24 for a /24 subnet
- 3 Click Calculate to see network address, broadcast address, host range, and total hosts
Use Cases
Plan IP address allocation for your infrastructure with precise subnet boundaries and host counts.
Quickly determine if two IP addresses are on the same subnet when diagnosing network issues.
Define firewall rules and access control lists with exact subnet ranges and wildcard masks.
FAQ
CIDR (Classless Inter-Domain Routing) notation expresses an IP address with its prefix length, e.g. 192.168.1.0/24, where /24 means the first 24 bits define the network.
A /24 subnet has 256 total addresses and 254 usable host addresses (the network and broadcast addresses are reserved).
A wildcard mask is the inverse of the subnet mask. It is used in ACL rules and OSPF configurations to define which bits of an address should be matched.
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