Subnet Calculator
IPv4 CIDR subnet solver — network, broadcast, mask, wildcard, host range and usable hosts.
Reviewed by the WorldCalcs team · Methodology · Last reviewed: July 2026
CIDR
192.168.1.10/24
- Network address
- 192.168.1.0
- Broadcast address
- 192.168.1.255
- Subnet mask
- 255.255.255.0
- Wildcard mask
- 0.0.0.255
- First usable host
- 192.168.1.1
- Last usable host
- 192.168.1.254
- Usable hosts
- 254
- Total addresses
- 256
What is a subnet calculator?
A subnet calculator works out the network details for an IPv4 address and a CIDR prefix (the "/24" style number). From just an IP and a prefix it gives you the network address, the broadcast address, the subnet mask, the usable host range and how many devices the subnet can hold. It saves you doing the binary maths by hand.
How subnetting works
The prefix tells you how many bits at the start of the address are fixed for the network. A /24 fixes the first 24 bits, leaving 8 bits for hosts. The subnet mask is those fixed bits written in dotted form (255.255.255.0 for a /24), and the wildcard mask is its inverse (0.0.0.255).
- Network address = IP AND subnet mask (all host bits set to 0)
- Broadcast address = network address with all host bits set to 1
- Total addresses = 2 raised to the number of host bits
- Usable hosts = total − 2 (the network and broadcast addresses are reserved)
Worked example
For 192.168.1.10/24 the mask is 255.255.255.0. The network address is 192.168.1.0 and the broadcast is 192.168.1.255. Usable hosts run from 192.168.1.1 to 192.168.1.254 — that is 254 addresses (256 total, minus network and broadcast).
Special cases: /31 and /32
Two prefixes break the "minus two" rule. A /31 has just two addresses and, under RFC 3021, both are usable on point-to-point links, so usable = 2. A /32 is a single host address (often used for one machine or a loopback), so usable = 1.
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Results are estimates and may contain errors — for general information only, not professional advice. Always verify before relying on them. Disclaimer
How to use
Enter the four octets of an IPv4 address and choose a CIDR prefix (/0 to /32). The tool computes the network address, broadcast, subnet mask, wildcard mask, first and last usable host, and totals.
Special cases: /31 gives 2 usable hosts (RFC 3021 point-to-point), and /32 is a single host.