Free Online Network & IP Address Tools
Network engineering is the invisible foundation of every application. Whether you are designing a cloud VPC, writing firewall rules, planning a data center migration, or debugging a routing issue, precise network calculations are essential. This suite of IPv4 and IPv6 tools provides instant subnet breakdowns, address format conversions, range expansions, and identifier generation — all without installing network analysis software. Every calculation runs client-side in your browser, making these tools safe to use with private internal IP ranges and sensitive network topologies.
Common Use Cases
6 Tools in This Category
In-Depth Guide: Free Online Network & IP Address Tools
IPv4 Subnetting: A Complete Guide
IPv4 subnetting divides a large address block into smaller, more manageable subnetworks. CIDR (Classless Inter-Domain Routing) notation makes this compact and precise. **CIDR Notation Explained** A CIDR address like `192.168.1.0/24` has two components: - `192.168.1.0` — the network address (all host bits = 0) - `/24` — the prefix length (first 24 bits identify the network, remaining 8 bits identify hosts) With /24, there are 2⁸ = 256 addresses total: - 1 network address (192.168.1.0) - 254 usable host addresses (192.168.1.1 – 192.168.1.254) - 1 broadcast address (192.168.1.255) **Common CIDR Sizes** | CIDR | Total Addresses | Usable Hosts | Typical Use | |------|----------------|--------------|-------------| | /30 | 4 | 2 | Point-to-point links | | /29 | 8 | 6 | Small office | | /28 | 16 | 14 | Department segment | | /24 | 256 | 254 | Standard LAN subnet | | /22 | 1,024 | 1,022 | Mid-size office | | /16 | 65,536 | 65,534 | Large network | | /8 | 16,777,216 | 16,777,214 | ISP/Class A | **Private IP Ranges (RFC 1918)** These ranges are reserved for private networks and are not routable on the public internet: - 10.0.0.0/8 (Class A private — 16.7M addresses) - 172.16.0.0/12 (Class B private — 1M addresses) - 192.168.0.0/16 (Class C private — 65,536 addresses)
IPv6 and the Case for ULA Addresses
IPv6 was designed to replace IPv4's exhausted 32-bit address space with 128-bit addresses — providing 3.4×10³⁸ possible addresses. While global IPv6 adoption is still in progress, most cloud providers and enterprise networks already dual-stack. **IPv6 address structure:** 8 groups of 4 hexadecimal digits: `2001:0db8:85a3:0000:0000:8a2e:0370:7334` Leading zeros can be omitted; consecutive all-zero groups are replaced with `::` **ULA (Unique Local Addresses — RFC 4193)** ULA addresses (fc00::/7) are the IPv6 equivalent of RFC 1918 private addresses. They are not routable on the public internet and are intended for use within private networks. The format is: - `fd` — ULA prefix (indicates locally assigned) - 40 bits of pseudo-random global ID (making collisions statistically unlikely when networks merge) - 16-bit subnet ID - 64-bit interface ID Our IPv6 ULA Generator creates properly formatted ULA prefixes with cryptographically random global IDs — suitable for assigning to VLANs, VPC subnets, and private Kubernetes pod networks.
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation combines an IP address with a prefix length: 192.168.1.0/24. The /24 means the first 24 bits identify the network, leaving 8 bits for host addresses (256 total, 254 usable).
How many hosts does a /24 subnet support?
A /24 subnet has 256 total addresses (2⁸). Subtract the network address and broadcast address, leaving 254 usable host addresses. Our subnet calculator shows all values instantly for any CIDR block.
What is the difference between /24 and /16?
/24 provides 256 addresses (254 usable). /16 provides 65,536 addresses (65,534 usable). Each step down in prefix length doubles the address space: /23 = 512, /22 = 1024, etc.
What are the private IPv4 ranges?
RFC 1918 defines three private ranges not routable on the public internet: 10.0.0.0/8 (Class A, ~16M addresses), 172.16.0.0/12 (Class B, ~1M addresses), and 192.168.0.0/16 (Class C, 65,536 addresses).
What is a MAC address used for?
A MAC (Media Access Control) address is a 48-bit hardware identifier assigned to every network interface. It operates at OSI Layer 2 for local network communication. Unlike IP addresses, MAC addresses are not routable across the internet. Virtual machines and containers often require randomly generated MAC addresses.