100% In-Browser Calculation • Zero Network Transmissions • Instant Bitwise Math

IPv4 Subnet & CIDR Calculator

Calculate IP network ranges, usable host capacities, broadcast addresses, wildcard masks, and bitwise binary breakdowns for network planning, cloud VPCs, and Cisco certification.

Valid IPv4
Common Presets:

Network Calculation Results

Network Address
--
Subnet Route ID
Broadcast Address
--
All-host multicast
Usable Host Range
--
-- usable IPs
Subnet & Wildcard Mask
--
Wildcard: --
Property Value Hexadecimal / Details Action
CIDR Representation -- -- bits prefix
IP Address Classification -- --
Total Addresses -- 2^(32-N)
Subnet Mask (Hex) -- 32-bit big-endian
IP in Integer Format -- Unsigned 32-bit int

Bitwise Binary Visualisation

Network Bits Host Bits
IP Address Binary:
--
Subnet Mask Binary:
--
Network Route Binary (IP AND Mask):
--
Broadcast Binary (IP OR NOT Mask):
--

Subnet Division & Sub-allocation

Partition this network block into smaller constituent subnets

Subnet Network Address Usable Host Range Broadcast Address Hosts

CIDR Subnet Reference Cheat-Sheet

CIDR Subnet Mask Wildcard Mask Total Addresses Usable Hosts

Understanding IPv4 Subnetting & CIDR Notation

Classless Inter-Domain Routing (CIDR) replaced historic class-based IPv4 network allocations in 1993, allowing variable-length subnet masking (VLSM) to prevent exhaustion of global IPv4 address spaces. An IPv4 address comprises 32 binary bits grouped into four 8-bit octets separated by decimal periods.

A subnet mask delineates where the network prefix ends and where local host identifiers begin. For example, in a standard home or small-office network configured with 192.168.1.0/24, the first 24 bits represent the network route (255.255.255.0), leaving 8 bits for host addressing. This yields 256 total IP addresses, of which 254 are assignable to devices after reserving the network address and broadcast address.

🔒

Private RFC 1918 Ranges

Reserved for internal private intranets: 10.0.0.0/8 (16.7M IPs), 172.16.0.0/12 (1.04M IPs), and 192.168.0.0/16 (65.5k IPs).

⚡

Zero Server Computation

All bitwise AND, OR, and XOR calculations execute instantaneously in your browser using 32-bit unsigned bitwise integer arithmetic with zero telemetry.

☁️

Cloud VPC Ready

Easily divide Amazon Web Services (AWS), Microsoft Azure, and Google Cloud VPC CIDR blocks across availability zones and public/private tiers.

Frequently Asked Questions

Why are two IP addresses subtracted from the usable host count?

In standard IPv4 subnets (such as /24 to /30), the first address represents the Network ID (all host bits set to 0), and the final address represents the Broadcast Address (all host bits set to 1). Neither can be assigned to an individual network interface card. (Note: In /31 point-to-point links defined under RFC 3021, both IPs may be assigned).

What is a wildcard mask and where is it used?

A wildcard mask is the exact bitwise inverse of the subnet mask (255.255.255.255 - Subnet Mask). It is predominantly used in Cisco IOS Access Control Lists (ACLs) and OSPF routing protocol configuration to specify match criteria for packet filters.

Can I paste an IP address that already includes CIDR notation?

Yes. If you paste an address such as 10.0.4.0/22 into the input field, the calculator will automatically extract the prefix, adjust the dropdown selector, and compute the network parameters immediately.