Complete Documentation — All Tools & Calculators

The homepage calculator combines four tools in a single interface — a live subnet details panel, FLSM calculator, VLSM calculator, and Supernetting (Route Summarization) tool. It is the fastest way to go from an IP address and mask to a full set of subnet details without switching pages.

1. 1IP Address & Mask — Enter any IPv4 address and set the subnet mask by typing it directly or dragging the CIDR slider. The Subnet Details panel updates live as you change the slider.
2. 2FLSM mode — Check the FLSM checkbox, enter a Quantity and a single Hosts per Subnet value, then click Calculate to split the network into equal subnets.
3. 3VLSM mode — Check the VLSM checkbox, enter comma-separated host counts (e.g. 100,50,20), then click Calculate to create variable-size subnets.
4. 4Supernetting — Paste two or more networks (one per line) into the Supernetting box and click Calculate to generate a summary route.
5. 5Click Clear All to reset every field at once.

The dedicated Subnet Calculator focuses entirely on a single subnet — it takes any IPv4 address and prefix and instantly shows you all the key properties of that network in a clean details table. Use it when you need the full breakdown of one specific network without any FLSM or VLSM overhead.

FLSM divides a network into equal-sized pieces — every subnet gets the same number of addresses. It is the simplest subnetting method because every subnet uses the same mask. Use it when all your network segments need roughly the same number of devices.

1. 1Enter your base IP Address and set the Subnet Mask or CIDR slider to define your total address pool.
2. 2Enter the Quantity — how many equal subnets you want to create.
3. 3Enter Hosts per Subnet — a single number representing the maximum devices per subnet (e.g. 50).
4. 4Click Calculate FLSM. Results appear in the subnets table and any leftover addresses appear in the Free/Unused IP table.

VLSM lets you give each subnet exactly the size it needs — no more, no less. One subnet can hold 100 devices while another holds 10, all carved from the same parent block. This wastes far fewer addresses than FLSM when your segments vary in size.

1. 1Enter your base IP Address and set the CIDR to define the total pool.
2. 2In Required Hosts per Subnet, enter a comma-separated list of host counts — one value per subnet, e.g. 100, 50, 20. The Quantity field auto-counts as you type.
3. 3Click Calculate VLSM. The calculator sorts your values largest-first automatically, then allocates subnets in order.

Supernetting is the opposite of subnetting. Instead of breaking one large network into pieces, it combines multiple smaller networks into one single summary route — reducing the number of entries in a routing table. Also called Route Summarization or IP Aggregation.

1. 1Contiguous — Networks must sit next to each other with no gaps in the address space.
2. 2Power of 2 — Summarize 2, 4, 8, or 16 networks. Odd numbers force over-summarization.
3. 3Boundary aligned — The first network must start at an address evenly divisible by the total block size, or the summary will cover addresses outside your intended range.

1. 1Type each network in CIDR format in the text box — one network per line, e.g. 192.168.0.0/24.
2. 2Enter at least two networks. Order does not matter — the calculator sorts them automatically.
3. 3Click Calculate Summary Route. The result shows the summary network details and an Individual Networks breakdown table confirming each input is included.

Subnet overlap occurs when two network ranges share one or more IP addresses. Overlapping subnets cause routing conflicts — the router cannot determine which path to use for a packet. This is critical to check before configuring VPC peering, VPN tunnels, or merging two networks.

1. 1Enter the first network or IP in the Network 1 field (e.g. 10.0.0.0/16).
2. 2Enter the second network or IP in the Network 2 field (e.g. 10.0.50.0/24).
3. 3Click Check For Overlap. A status banner appears instantly along with a comparison table showing the exact start and end IP boundaries of both networks.

This tool expands a CIDR block into a complete list of every usable IP address it contains — each one on its own line, ready to copy. For example, a /29 network contains 6 usable host addresses. Use it when you need a full address inventory for firewall rules, audit documentation, or DHCP pool planning.

1. 1Define your network — enter the IP address and set the prefix using the subnet mask field or CIDR slider.
2. 2Generate the list — click the Generate button to produce every usable host address in the block.
3. 3Export — copy the list directly into firewall allow/deny rules, audit spreadsheets, or network documentation.

A professional diagnostic tool that instantly identifies the legacy Class of an IPv4 address or the modern Scope and Type of an IPv6 address. By analysing the leading bits of any IP address, the detector reveals how hardware categorises the address for routing, multicasting, or private networking.

1. 1Enter your address — type or paste any IPv4 (e.g. 172.16.0.1) or IPv6 (e.g. fe80::1) address into the input field.
2. 2Detect Properties — click the button to perform a bitwise analysis of the leading octet or hex digits.
3. 3Analyse Results — view the protocol version, the legacy class (for IPv4), or the reachability scope (for IPv6) alongside the default mask and private/public status.

The class is determined strictly by the leading bits of the first octet. If the first bit is 0, it is Class A. If it starts with 10, it is Class B. If it starts with 110, it is Class C. This binary logic allowed early routers to handle traffic efficiently before CIDR was invented.

IPv4 classful addressing was found to be extremely wasteful — a company needing 500 addresses had to take an entire Class B (/16 with 65,534 hosts). IPv6 abandoned this system entirely in favour of a hierarchical prefix and scope model. Instead of a class, IPv6 uses the leading bits to indicate scope: whether the address is intended for a single link (fe80::/10 Link-Local), a private organisation (fc00::/7 Unique Local), or the global internet (2000::/3 Global Unicast). The tool detects all of these automatically for any address you enter. The modern internet uses CIDR for IPv4 too, making classes obsolete in practice — but they remain essential knowledge for CCNA, Network+, and other IT certification exams.

A pre-calculated reference table listing all 33 IPv4 prefix lengths from /0 to /32 — each with subnet mask, wildcard mask, total addresses, usable host count, class, and a description of common use. Also includes the three RFC 1918 private address ranges. Bookmark it and keep it open during exams, router configuration, and firewall rule writing.

Enter any IPv6 address and set a prefix length from /0 to /128. The calculator instantly expands the address to its full 128-bit form, compresses it to its shortest form, splits it into Network Prefix and Host (Interface ID) portions, shows the first and last addresses in the block, calculates the total address count, detects the address type and scope, and tells you how many /64 subnets fit inside the block.

SLAAC (Stateless Address Autoconfiguration) allows an IPv6 host to generate its own unique IP address without a DHCPv6 server. The device takes the /64 network prefix advertised by the router and combines it with a 64-bit Interface Identifier it creates itself. The EUI-64 (Extended Unique Identifier) method generates that Interface ID from the device's 48-bit MAC address.

1. 1 FF:FE Insertion — The 48-bit MAC address is split into two 24-bit halves (the OUI and the device-specific portion). The 16-bit hex value FFFE is inserted between them, expanding the 48-bit MAC into a 64-bit Interface Identifier.
2. 2 7th Bit Flip (U/L Bit) — The 7th bit of the first octet (the Universal/Local bit) is inverted. A 0 becomes 1, indicating the address is universally unique. This is why a MAC starting with 00 becomes 02 in EUI-64.

1. 1MAC Address — paste your device's hardware address. The tool accepts any separator format: colons (:), hyphens (-), or Cisco dots (.).
2. 2Network Prefix (optional) — enter your /64 prefix (e.g. 2001:db8::) to see the complete SLAAC-generated IPv6 address, not just the Interface ID.
3. 3Click Generate — review the step-by-step breakdown showing the FFFE insertion, the bit flip, and the final Interface Identifier.

Worked Example — MAC: 00:00:AA:11:22:33

IPv6 addresses are 128-bit strings — writing them out in full produces 32 hex characters split into 8 groups of 4. To make them manageable, network engineers use compressed notation. This tool converts freely between the Expanded form (all 32 digits shown) and the Compressed form (using the :: shortcut). Both formats represent the exact same address — the compressed version is simply shorthand for human readability.

1. 1Paste your IPv6 address into the input field. The tool is flexible — you can enter a messy, partially compressed, or fully expanded address in any valid format.
2. 2Click Format Address to see the results. If the input is invalid an error message will appear.

Three reference tables in one page: a prefix length table covering /0 to /128 with total address counts and /64 subnet counts; a full address types table covering all 11 IPv6 address categories with scope and routability; and a well-known multicast addresses table. The most comprehensive IPv6 quick-reference available — bookmark it alongside the IPv4 chart.

As networks migrate from IPv4 to IPv6, devices on pure IPv6 networks still need to communicate with legacy IPv4 systems. Transition mechanisms embed a 32-bit IPv4 address inside a 128-bit IPv6 address in different ways depending on the protocol.

Firewalls, routers, cloud security groups (AWS, Azure, GCP), and routing protocols all require CIDR notation — they do not accept arbitrary IP ranges like "192.168.0.10 to 192.168.0.50". This tool converts any start-to-end IP range into the minimum set of CIDR blocks that covers it exactly.

1. 1Enter the Start IP of your range, e.g. 192.168.0.10.
2. 2Enter the End IP of your range, e.g. 192.168.0.50.
3. 3Click Convert to CIDR. The tool outputs the smallest list of CIDR blocks that covers every address from start to end with no gaps and no excess.

Converts any IPv4 or IPv6 address into binary, hexadecimal, and integer formats. Automatically detects which type of address you have entered. Useful for packet analysis, database work, and low-level protocol debugging.

A wildcard mask is the bitwise inverse of a subnet mask. A 0 bit means "this bit must match" and a 1 bit means "this bit can be anything". Wildcard masks are used in Cisco IOS access control lists (ACLs) and OSPF network statements to define which bits of an address a rule applies to.

A reverse DNS (PTR) record maps an IP address back to a hostname — the opposite of the normal forward DNS lookup. To store PTR records, DNS uses a special reversed notation. For IPv4, the octets are reversed and .in-addr.arpa is appended. For IPv6, each nibble (hex character) is reversed individually and .ip6.arpa is appended.

A MAC (Media Access Control) address is a 48-bit hardware identifier assigned to every network interface. Different vendors and operating systems display the same MAC address in different formats. This tool converts between all common formats instantly. Paste any valid MAC in any format and get every other format back.

Paste a messy block of text containing IP addresses — log files, firewall exports, spreadsheet dumps, emails — and the IP Cleaner extracts every valid IPv4 and IPv6 address, removes duplicates, sorts them, and gives you back a clean deduplicated list ready to use. It strips out all surrounding text, punctuation, and noise automatically.

1. 1Paste any text containing IP addresses into the input box — the format does not matter, IPs can be mixed with other text.
2. 2Click Clean IPs. The tool parses every valid address and outputs a clean sorted list.
3. 3Copy the result directly into your firewall rules, access lists, or documentation.