Tool
Subnet Calculator
Enter an IPv4 address and CIDR prefix to calculate the network and broadcast address, subnet mask, wildcard and usable host range. Updates instantly.
Subnet Details
- Network Address
- 192.168.1.0
- Usable Host Range
- 192.168.1.1 – 192.168.1.254
- Broadcast Address
- 192.168.1.255
- Usable Hosts
- 254
- Subnet Mask
- 255.255.255.0
- Wildcard Mask
- 0.0.0.255
- CIDR Notation
- 192.168.1.0/24
- Total Addresses
- 256
- IP Class
- C
- Address Type
- Private (RFC 1918)
How to Use the Subnet Calculator
Type an IPv4 address and pick a CIDR prefix (the /24 part). The
calculator instantly derives the whole subnet. You can also paste a full CIDR like 10.0.0.0/8 into the address field, and the prefix selector updates automatically.
- Network address: the first address; names the subnet.
- Broadcast address: the last address; reaches every host at once.
- Usable host range: the addresses you can actually assign to devices.
- Subnet & wildcard mask: which bits are network vs host.
The values here describe how an address block is divided into a network, not the public address the internet sees. To check the public IP your network presents, use the What Is My IP Address tool, or look up any address with the IP address lookup.
Frequently Asked Questions
What is a subnet calculator?
A subnet calculator takes an IP address and a CIDR prefix (like /24) and works out the network address, broadcast address, subnet mask, wildcard mask, the range of usable host addresses and how many hosts the subnet holds.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation writes a network as an address followed by a slash and a prefix length, e.g. 192.168.1.0/24. The prefix is how many leading bits form the network portion: /24 means the first 24 bits, leaving 8 bits for hosts.
What is a subnet mask?
A subnet mask marks which part of an IP address identifies the network and which part identifies the host. For a /24 the mask is 255.255.255.0: the three 255 octets cover the 24 network bits and the final 0 covers the 8 host bits. Devices compare addresses against the mask to decide whether another address is on the same local network.
How many usable hosts are in a /24?
A /24 has 256 total addresses and 254 usable host addresses. Two addresses are reserved: the network address (the first) and the broadcast address (the last), which cannot be assigned to a device.
What is the difference between the network and broadcast address?
The network address is the first address in the subnet and identifies the network itself. The broadcast address is the last address and is used to send data to every host in the subnet at once. Neither can be assigned to an individual device.
What is a wildcard mask?
A wildcard mask is the inverse of the subnet mask (every bit flipped). For 255.255.255.0 the wildcard is 0.0.0.255. It is used by routing and access-control rules, for example in Cisco ACLs and OSPF.
What do /31 and /32 mean?
A /32 describes a single host (one address). A /31 describes a two-address point-to-point link; under RFC 3021 both addresses are usable, with no separate network or broadcast address.
What is the IP Class shown in the results?
The IP Class (A, B, C, D or E) is legacy classful information from before CIDR existed. Modern networks use CIDR prefixes, not classes, to size networks, so the class no longer determines how an address block is split. It is shown here for reference only.