SUBNET · CIDR · NETWORK CALCULATOR

IP Subnet Calculator

Work out subnet masks, network ranges, and IP address details for any IPv4 network.

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Provide an IPv4 address along with a subnet mask or CIDR notation.

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What a subnet calculator does and why network engineers rely on one

A subnet calculator takes an IP address written in CIDR notation, such as 192.168.1.0/24 , and derives every boundary value that defines that subnet. The prefix length tells the calculator how many bits belong to the network portion of the address. From that single input, it computes the network address, broadcast address, subnet mask, wildcard mask, total address count, usable host range, and the number of assignable host addresses.

Without these values, planning address space is guesswork. Getting a boundary wrong by even one bit can cause routing failures or wasted address blocks.

What the tool calculates and how to read the output

The IP Subnet Calculator on Pingie performs every calculation in your browser using JavaScript. No data leaves your device. Enter an IPv4 address with a CIDR prefix length anywhere from /0 to /32, and the results appear immediately.

The output covers seven values:

  • Network address - the first address in the block, which identifies the subnet itself and cannot be assigned to a host.
  • Broadcast address - the last address, reserved for sending packets to every host on the subnet simultaneously.
  • Subnet mask - displayed in dotted-decimal format (for example, 255.255.255.0 ), showing which bits are network bits.
  • Wildcard mask - the bitwise inverse of the subnet mask, commonly used in access control lists and routing protocol configurations.
  • Total addresses - the full count of addresses in the block, including the network and broadcast addresses.
  • Usable host range - the first and last addresses that can actually be assigned to devices.
  • Number of usable hosts - the count of assignable addresses, which equals total addresses minus two for every prefix shorter than /31.

How to use the subnet calculator

  1. Open the IP Subnet Calculator from the tool menu on Pingie .
  2. Type your IP address and prefix length in CIDR notation into the input field. For example: 10.0.0.0/8 or 172.16.4.128/26 .
  3. The calculator displays all seven output values without any page reload or form submission.

The netmask calculator accepts any valid IPv4 CIDR prefix. If you need to verify connectivity to a specific host after you have planned your address space, the ping tool can confirm reachability.

Common situations where subnet planning matters

Network engineers, system administrators, and security teams reach for a network subnet calculator in several recurring scenarios:

  • Designing a new office or data center network and allocating address blocks to each VLAN or segment.
  • Verifying that two IP addresses fall within the same subnet before troubleshooting a routing issue.
  • Writing firewall rules or access control lists that require a wildcard mask instead of a prefix length.
  • Splitting a large block into smaller subnets to reduce broadcast domain size or enforce network segmentation.
  • Documenting IP address assignments for audits or change management records.
  • Studying for networking certifications where subnetting questions appear frequently.

How this tool compares to related network utilities

A subnet netmask calculator works purely with address math. It does not query any external service. Tools that do query external services include the DNS lookup tool , which sends a query to a resolver and returns live record data, and the ASN lookup , which queries routing registries to identify which organization owns a prefix. The subnet calculator, by contrast, derives all output from the binary structure of the address you provide. There is no network round-trip and no dependency on external data freshness.

The IP converter is a related tool that translates an IP address between decimal, binary, hexadecimal, and integer formats without performing subnet boundary calculations. Use the subnet calculator when you need boundary values; use the IP converter when you need a different numeric representation of the same address.

FAQ

A subnet calculator applies binary arithmetic to an IPv4 address and a CIDR prefix length to derive the boundaries of the subnet. It performs bitwise AND operations between the address and the subnet mask to find the network address, then sets all host bits to one to find the broadcast address. Every other output value follows from those two results. The tool removes the need to do that binary math by hand.

CIDR (Classless Inter-Domain Routing) notation expresses a subnet as an IP address followed by a slash and a prefix length, for example 192.168.1.0/24 . The prefix length is simply the count of consecutive one-bits in the subnet mask. A /24 prefix equals the dotted-decimal mask 255.255.255.0 . The two formats are mathematically identical; CIDR is more compact and is the standard in modern routing and configuration.

The subnet mask uses one-bits to mark the network portion and zero-bits for the host portion. The wildcard mask is the bitwise inverse: zero-bits mark fixed (network) bits and one-bits mark variable (host) bits. Cisco IOS access control lists and OSPF network statements use wildcard masks rather than subnet masks. For a /24, the subnet mask is 255.255.255.0 and the wildcard mask is 0.0.0.255 . Both are shown in the output of this calculator.

The network address (all host bits set to zero) identifies the subnet in routing tables and cannot be assigned to a device. The broadcast address (all host bits set to one) is reserved for layer-3 broadcasts to every host on the segment. Assigning either address to a device would cause routing or broadcast conflicts. So a /24 block has 256 total addresses but only 254 usable host addresses.

No. All calculations run entirely in your browser using JavaScript. The address you enter never leaves your device and is not transmitted to Pingie's servers or any third party. This is possible because subnet math is deterministic arithmetic that requires no external data. You can verify this by watching your browser's network activity tab while using the tool.

The calculator accepts any IPv4 CIDR prefix from /0 to /32. A /0 covers the entire IPv4 address space (4,294,967,296 addresses). A /32 describes a single host address with no usable host range beyond that address itself. Prefixes of /31 are a special case defined in RFC 3021 for point-to-point links, where both addresses are usable and there is no traditional broadcast address.

The IP Subnet Calculator currently supports IPv4 CIDR notation only, with prefix lengths from /0 to /32. IPv6 uses a 128-bit address space and different subnetting conventions. If you need to test whether a website or server is reachable over IPv6, the IPv6 website test tool on Pingie can check that connectivity for you.

A subnet calculator performs pure binary arithmetic on the address and prefix you provide. It queries no external service and produces the same result every time for the same input. A DNS lookup tool sends a live query to a DNS resolver and returns records that can change over time as zone data is updated. Use the subnet calculator for address planning; use DNS lookup to resolve hostnames or verify record configurations.

The prefix length controls how many host addresses exist in the subnet. Each time you extend the prefix by one bit, you halve the number of addresses. A /24 provides 254 usable hosts; a /25 provides 126; a /26 provides 62. Choose the shortest prefix that accommodates your expected device count plus reasonable growth headroom, while keeping the block small enough to limit broadcast traffic and maintain clear network segmentation.

Yes. Enter the first IP address with the relevant prefix length and note the usable host range in the output. Then check whether the second IP address falls within that range. If it does, both addresses share the same subnet and can communicate at layer 2 without routing. This is a common first step when troubleshooting a situation where two devices cannot reach each other despite appearing to be on the same network.

The tool accepts an IPv4 address combined with a CIDR prefix length in the format address/prefix , for example 10.10.0.0/16 or 192.168.100.64/27 . The host bits in the address do not need to be zeroed out before entry; the calculator derives the correct network address regardless of which host address within the block you enter.

Yes. The IP Subnet Calculator on Pingie is free with no account required. Because all computation happens in the browser and no server resources are consumed per calculation, there is no usage limit or rate restriction. You can calculate as many subnets as needed in a single session without signing in or providing any personal information.