Subnet Calculator
Network, broadcast, usable hosts and masks for an IPv4 CIDR block.
Quick answer
- Formula: Network = IP AND mask; Broadcast = Network OR (NOT mask); Hosts = 2^(32 − prefix)
- Worked example — Network address: 192.168.1.0 (full example below).
Subnet Calculator
| Network address | 192.168.1.0 |
| Broadcast address | 192.168.1.255 |
| First usable host | 192.168.1.1 |
| Last usable host | 192.168.1.254 |
| Total addresses | 256 |
| Usable hosts | 254 |
| Subnet mask | 255.255.255.0 |
| Wildcard mask | 0.0.0.255 |
192.168.1.10/24 sits in network 192.168.1.0 with broadcast 192.168.1.255 and 254 usable hosts, .1 through .254.
Enter an IPv4 address and a CIDR prefix length to get the network address, broadcast address, first and last usable host addresses, the subnet and wildcard masks, and the host counts for the block.
For prefixes /0 to /30, two addresses per block are reserved (network and broadcast), leaving total − 2 usable hosts. The special cases follow common practice: a /31 point-to-point link has 2 usable addresses and a /32 is a single host route.
The formula
Worked example
192.168.1.10/24 sits in network 192.168.1.0 with broadcast 192.168.1.255 and 254 usable hosts, .1 through .254.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
Why does a /24 have 254 usable hosts, not 256?
A /24 block has 2^8 = 256 addresses, but the first is the network address and the last is the broadcast address, leaving 254 for hosts.
What is a wildcard mask used for?
It is the bitwise inverse of the subnet mask and is used in router ACLs and OSPF statements, where 0 bits mean 'must match' and 1 bits mean 'ignore' — the opposite convention to a subnet mask.
Category: Everyday Life calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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