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Use this result
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What does this calculator estimate?
192.168.1.10/24 has network address 192.168.1.0, broadcast 192.168.1.255, 256 addresses, and 254 usable hosts. Address count = 2^(32 - prefix); usable hosts = count - 2.
- Network address = IP AND mask; broadcast = network OR (~mask) (Wikipedia).
- /24 gives 256 addresses and 254 usable hosts.
- Usable hosts exclude the network and broadcast addresses.
What subnetting is for
Subnetting divides a network into address blocks so traffic stays local and address space is used efficiently. CIDR notation (/24) states how many bits are the network portion — the rest are host bits.
Limitations to watch for
The tool assumes IPv4 CIDR. The first and last addresses in a subnet are reserved (network and broadcast), so usable hosts = total − 2. Classful assumptions (A/B/C) are obsolete — always use the prefix.
How to use it in practice
Enter an IP on your network and its prefix (typically /24 for home LANs) to see the network range, broadcast address, and usable host range. Use the numbers for static IP configuration, DHCP scopes, and firewall rules.
['Enter an IPv4 address.', 'Enter the CIDR prefix (0–32).', 'Read the network, broadcast, count, and usable range.']
How this calculator works
Formula
From an IP and CIDR prefix (/n): network address = IP AND mask; broadcast = network OR (~mask); address count = 2^(32−n); usable hosts = count − 2. Example: 192.168.1.10/24 → network 192.168.1.0, broadcast 192.168.1.255, 254 usable hosts.
Worked example
192.168.1.10/24: network 192.168.1.0, broadcast 192.168.1.255, 256 addresses, 254 usable hosts.
Assumptions to verify
- IPv4 addressing and CIDR notation are used.
- Standard network/broadcast reservations apply.
- No VLSM or supernetting nuances are modeled.
Frequently asked questions
How does a subnet calculator work?
It takes an IP and CIDR prefix, computes the network address (IP AND mask), broadcast (network OR ~mask), address count 2^(32−n), and usable hosts minus 2.
What is CIDR notation?
The /n suffix stating how many bits are the network portion — /24 means 24 network bits and 8 host bits (256 addresses).
How many usable hosts are in a /24?
256 total minus 2 reserved (network + broadcast) = 254 usable hosts.
What are the network and broadcast addresses?
The network is the first address (identifies the subnet); the broadcast is the last (sent to all hosts). Both are reserved.
What prefix should my home network use?
Typically /24 (255.255.255.0) — 254 usable addresses, plenty for home use.
Is this for IPv6?
No — the tool handles IPv4 CIDR. IPv6 uses similar concepts but different notation.
Why can't I use the first and last addresses?
They're reserved by protocol for the network identifier and broadcast — assigning them to hosts breaks the subnet.
Cite this tool
BoringToolsKit. “Subnet Calculator.” boringtoolskit.com/subnet-calculator/ (reviewed 2026-08-25). Free to reference in articles, syllabi, and answer posts with a link.
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