IPv4 Subnet Calculator
Calculate IPv4 network address, broadcast address, usable host IP range, wildcard mask, and binary bitwise breakdown.
IP Address & Subnet Prefix
Bitwise Binary Decomposition (32 Bits)
11000000.10101000.00000001.10010110
11111111.11111111.11111111.00000000
11000000.10101000.00000001.00000000
Subnet Boundary Addresses
192.168.1.0
192.168.1.255
192.168.1.1 — 192.168.1.254
0.0.0.255
⚖️ Decision Verdict: /24 Standard Subnet
Network 192.168.1.0/24 allocates 254 assignable host addresses (192.168.1.1 through 192.168.1.254). IP 192.168.1.0 is reserved as the wire Network ID, and 192.168.1.255 is the broadcast target.
Subnet Capacity & Routing Telemetry
About this tool
How to use it
- Enter any valid IPv4 address (e.g., 192.168.1.150, 10.0.0.1, or 172.16.50.25).
- Select your CIDR prefix length (/0 to /32) or corresponding dotted-decimal subnet mask.
- View instant network boundaries: Network ID, Broadcast IP, and usable host address range.
- Inspect the 32-bit binary bitwise breakdown comparing IP, Subnet Mask, and Network ID.
- Review IP scope classifications (RFC 1918 Private Class A/B/C vs Public Routable, loopback, or APIPA).
Why it matters
Subnetting divides a large physical or cloud network into smaller, logical, and secure broadcast domains. Network engineers and cloud architects use Classless Inter-Domain Routing (CIDR) to allocate IP address blocks efficiently, isolate subnets in AWS/GCP/Azure VPCs, prevent broadcast storms, and configure router ACL firewalls.
When to use it
Use this calculator when provisioning cloud VPC subnets, configuring firewalls, setting up DHCP scope pools, designing office LAN topologies, or studying for Cisco CCNA / CompTIA Network+ certifications.
Good to know
Reserved Addresses: In standard IPv4 subnets, two addresses are reserved and cannot be assigned to hosts: the first address (all host bits 0) is the Network ID, and the last address (all host bits 1) is the Directed Broadcast address.
Common questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation represents an IP address and its associated routing prefix length separated by a slash (e.g., 192.168.1.0/24). The number after the slash indicates how many leading bits of the 32-bit address are fixed for the network.
What are RFC 1918 private IP ranges?
RFC 1918 reserves three address blocks for internal private networks that are not routed on the public internet: 10.0.0.0/8 (Class A, 16.7 million IPs), 172.16.0.0/12 (Class B, 1.04 million IPs), and 192.168.0.0/16 (Class C, 65,536 IPs).
What is a wildcard mask?
A wildcard mask (frequently used in Cisco IOS Access Control Lists and OSPF routing) is the exact bitwise inverse of the subnet mask. For example, a /24 subnet mask (255.255.255.0) has a wildcard mask of 0.0.0.255.
Can you use a /31 subnet for point-to-point links?
Yes. Under RFC 3021, /31 subnets (which contain only 2 IP addresses) are officially supported on point-to-point links between routers, eliminating the requirement for separate network and broadcast addresses and conserving IPv4 address space.
Why does AWS reserve 5 IP addresses per subnet?
While standard IPv4 reserves 2 addresses (network and broadcast), Amazon Web Services (AWS) reserves 5 IP addresses in every VPC subnet: .0 (Network), .1 (VPC Router), .2 (DNS Server), .3 (Future use), and .255 (Broadcast).