YurlieIP Calculator
Enter any IPv4 address with optional prefix length to get full network details, binary representation, and subnet information.
Binary breakdown
Network
192.168.1.0192.168.1.255192.168.1.1192.168.1.254256254Masks
255.255.255.00.0.0.2550xFFFFFF00/2432322358760xC0A80164Octet breakdown
192C011000000168A810101000101000000011006401100100Anatomy of an IPv4 Address
Every IPv4 address contains 32 binary bits divided into two logical sections: the Network Portion (which designates the routing prefix) and the Host Portion (which designates the individual network interface).
When an IP is assigned a subnet mask (such as 192.168.1.100/24), the calculator computes four primary structural coordinates:
- Network Address (ID): The first address of the block (e.g.
192.168.1.0). All host bits set to0. - First Usable Host: Network Address + 1 (e.g.
192.168.1.1), commonly configured on default gateway routers. - Last Usable Host: Broadcast Address - 1 (e.g.
192.168.1.254). - Broadcast Address: The final address of the block (e.g.
192.168.1.255). All host bits set to1.
Historical Classful IP Addressing Scheme
Before CIDR was standardized in 1993, IPv4 address allocations were strictly bound to five historical classes based on the leading bits of the first octet:
| Class | Leading Bits | First Octet Range | Default Subnet Mask | Total Networks | Hosts per Network |
|---|---|---|---|---|---|
| Class A | 0... | 1 – 126 | 255.0.0.0 (/8) | 128 | 16,777,214 |
| Class B | 10... | 128 – 191 | 255.255.0.0 (/16) | 16,384 | 65,534 |
| Class C | 110... | 192 – 223 | 255.255.255.0 (/24) | 2,097,152 | 254 |
| Class D | 1110... | 224 – 239 | Unassigned (Multicast) | N/A | Multicast groups |
| Class E | 1111... | 240 – 255 | Unassigned (Experimental) | N/A | IETF Research reserve |
RFC 1918 & Special-Purpose IPv4 Address Blocks
| Address Block | Prefix Length | Scope / Specification | Usage & Purpose |
|---|---|---|---|
10.0.0.0 – 10.255.255.255 | /8 | RFC 1918 Private | Enterprise private LANs, Cloud VPCs, Data centers |
172.16.0.0 – 172.31.255.255 | /12 | RFC 1918 Private | Docker container bridges, Mid-sized corporate subnets |
192.168.0.0 – 192.168.255.255 | /16 | RFC 1918 Private | Home Wi-Fi routers, SOHO local subnets |
127.0.0.0 – 127.255.255.255 | /8 | RFC 1122 Loopback | Localhost internal IPC and software testing |
169.254.0.0 – 169.254.255.255 | /16 | RFC 3927 Link-Local | APIPA auto-assignment when DHCP server is unreachable |
100.64.0.0 – 100.127.255.255 | /10 | RFC 6598 Carrier NAT | Shared address space for ISP Carrier-Grade NAT |
Frequently Asked Questions
What is the difference between Classful and Classless (CIDR) IP addressing?
Classful addressing (RFC 791) originally grouped IPv4 into fixed Classes (A = /8, B = /16, C = /24) based on the first octet. Classless Inter-Domain Routing (CIDR, RFC 1519) abolished these rigid boundaries, allowing subnets to be partitioned at any bit prefix from /1 to /32 for efficient address allocation.
What are RFC 1918 Private IP addresses?
RFC 1918 reserves three address blocks for private internal networks: 10.0.0.0/8 (10.0.0.0 - 10.255.255.255), 172.16.0.0/12 (172.16.0.0 - 172.31.255.255), and 192.168.0.0/16 (192.168.0.0 - 192.168.255.255). These addresses are never routed over the public internet and require NAT (Network Address Translation).
What is an APIPA (Automatic Private IP Addressing) address?
An APIPA address (169.254.0.0/16, RFC 3927) is a link-local address that client operating systems (Windows, macOS) automatically self-assign when they fail to obtain an IP configuration from a local DHCP server.
What is the difference between the Network ID and the Broadcast address?
The Network ID is the very first address in a subnet where all host bits are binary 0, representing the entire network segment in routing tables. The Broadcast address is the very last address where all host bits are binary 1, used to send a single packet to every host on that local subnet.
What is Carrier-Grade NAT (CGNAT) 100.64.0.0/10?
Defined in RFC 6598, 100.64.0.0/10 (100.64.0.0 - 100.127.255.255) is reserved for ISPs to perform Carrier-Grade NAT (Large-Scale NAT), enabling internet service providers to connect thousands of residential customers using shared public IPv4 addresses without colliding with private RFC 1918 networks.