Network Address
192.168.1.0
First address in the subnet
Broadcast Address
192.168.1.255
Last address — packets sent to all hosts
First Usable Host
192.168.1.1
Lowest assignable host address
Last Usable Host
192.168.1.254
Highest assignable host address
Subnet Mask
255.255.255.0
/24 prefix length
Wildcard Mask
0.0.0.255
Inverse of subnet mask (used in ACLs)
Total Hosts
256
Usable Hosts
254
IP Class
C
Private Range
Yes (RFC 1918)
Binary
- Network
- 11000000.10101000.00000001.00000000
- Mask
- 11111111.11111111.11111111.00000000
Split into Subnets
New prefix /
About
The CIDR / Subnet Calculator takes any IPv4 address in CIDR notation (e.g. 192.168.1.0/24) and instantly calculates: network address, broadcast address, first and last usable host addresses, subnet mask, wildcard mask (used in Cisco ACLs and OSPF), total host count, usable host count, IP class (A/B/C/D/E), private/public range detection, and binary representations of both the network address and the subnet mask. The subnet split feature divides any parent network into smaller subnets by specifying a longer prefix length. Common subnet presets are provided for quick access. All calculations are pure JavaScript — no external library or server call is needed.
How to use
- 1 Type any IPv4 address in CIDR notation into the input box (e.g. 10.0.0.0/8 or 192.168.1.64/26).
- 2 Click any preset button to populate a commonly used network.
- 3 Network address, broadcast, host range, subnet mask, wildcard, and binary representations update instantly.
- 4 To split the subnet into smaller blocks, type a new (larger) prefix length and click Split.
- 5 The split results table shows each sub-network with its range, broadcast, and usable host count.
- 6 Click the copy icon next to any field to copy that value to your clipboard.
- What is CIDR notation?
- CIDR (Classless Inter-Domain Routing) notation represents an IP network as an address followed by a slash and a prefix length — for example, 192.168.1.0/24. The prefix length (0–32) specifies how many leading bits identify the network portion. /24 means 24 bits are the network and 8 bits are for hosts, giving 254 usable addresses.
- How many usable hosts does a subnet have?
- For prefix /n, total addresses = 2^(32-n). Two are reserved (network and broadcast), so usable hosts = 2^(32-n) − 2. Exception: /31 has 2 usable hosts (RFC 3021, used for point-to-point links); /32 is a single-host route.
- What is a wildcard mask and where is it used?
- A wildcard mask is the bitwise inverse of a subnet mask — 0-bits mean "match exactly" and 1-bits mean "any value." Used in Cisco ACLs and OSPF network statements. For example, the wildcard for /24 is 0.0.0.255.
- How do I find the network and broadcast address for a CIDR range?
- Network address = IP AND subnet mask. Broadcast = network OR wildcard mask. Example: 192.168.1.100 AND 255.255.255.0 = 192.168.1.0; then 192.168.1.0 OR 0.0.0.255 = 192.168.1.255. This tool performs both automatically.
- Is this tool 100% client-side?
- Yes. Pure JavaScript with no external API calls, no CDN library, and no server communication. All arithmetic runs locally in your browser — suitable for air-gapped networks or offline use.