IPv4 Subnet & CIDR Calculator with Binary Analysis
Calculate detailed IPv4 network configurations instantly. Enter an IP address and CIDR to find your subnet mask, wildcard mask, broadcast address, and usable host range. This tool even highlights the exact network bits in binary format!
IP Analysis Features
Full Subnet Breakdown: Network address, subnet mask, wildcard mask, broadcast address in one table
Usable Host Range: First and last assignable host addresses calculated automatically
CIDR Notation Support: Enter 192.168.1.1/24 or just 192.168.1.1 for class-default results
Binary Visualization: Every value shown in binary with network bits highlighted for instant comprehension
IP Address Class Detection: Identifies Class A, B, C, D (Multicast), or E (Experimental) automatically
Public vs Private Detection: Identifies Class A, B, C, D (Multicast), or E (Experimental) automatically
Subnet & Host Count: Total subnets and usable hosts calculated with full power-of-2 formula shown
Decimal Highlighting: Network octets highlighted in decimal for fast reading
Perfect for network engineers, students studying for CCNA, system administrators, IT professionals planning subnets, and anyone troubleshooting network configurations.
Frequently Asked Questions
An IP subnet calculator takes an IPv4 address and subnet mask (or CIDR prefix) and computes the complete network profile: the network address (the base address of the subnet), subnet mask (which bits identify the network), broadcast address (the last address in the subnet), usable host range (first to last assignable IP), and wildcard mask (the inverse of the subnet mask, used in ACLs). Our calculator also shows every value in binary with network bits highlighted making it the fastest way to understand exactly how any subnet is structured.
A CIDR prefix like /24 means the first 24 bits of the 32-bit address are the network portion. To convert to a dotted-decimal subnet mask, fill 24 bits with 1s and the remaining 8 with 0s: 11111111.11111111.11111111.00000000 = 255.255.255.0. For /16 it's 255.255.0.0, for /8 it's 255.0.0.0. Our calculator does this instantly, enter any IP with CIDR notation (e.g., 10.0.0.1/22) and the subnet mask, network address, broadcast, and host range all appear in both decimal and binary automatically.
These three values define the boundaries of any subnet. The network address is the first address in the subnet, it identifies the subnet itself and cannot be assigned to a host. The broadcast address is the last address packets sent here reach every device in the subnet and it also cannot be assigned. The usable host range is every address in between these are the IPs you can actually assign to computers, routers, and devices. For a /24 subnet, that's 256 total addresses, 254 usable hosts, with .0 as network and .255 as broadcast.
Private IP addresses (defined by RFC 1918) are reserved for internal networks and cannot be routed on the public internet, they must go through NAT to reach external destinations. The three private ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. Public IP addresses are globally routable and unique across the internet assigned by ISPs and regional registries. Loopback addresses (127.0.0.0/8) never leave the local device. Our calculator automatically detects which category any IP falls into, labeling it Private, Public, or Loopback.
The formula is 2^(32−CIDR) − 2. The exponent 32 − CIDR gives you the number of host bits, 2 raised to that power gives total addresses, and subtracting 2 removes the network and broadcast addresses. For /24: 2^8 − 2 = 254 usable hosts. For /22: 2^10 − 2 = 1,022 usable hosts. For /30: 2^2 − 2 = 2 usable hosts (common for point-to-point links). Our calculator shows the full formula with the actual exponents for every result, ideal for students learning subnetting math for CCNA or networking exams.