Master IP Subnetting with Ease
Calculate subnet masks, CIDR notation, network addresses, broadcast addresses, and usable host ranges instantly. Perfect for network engineers, students, and IT professionals.
Powerful IP Subnetting Tools
Everything you need to plan, calculate, and manage IP networks efficiently. From basic subnet calculations to advanced VLSM planning.
IPv4 Subnet Calculator
Calculate subnet masks, network addresses, broadcast addresses, and usable host ranges for any IPv4 network. Supports CIDR notation and custom masks.
Use Calculator →IPv6 Calculator
Work with IPv6 addresses effortlessly. Calculate prefix lengths, expand/compress addresses, and determine network ranges for next-generation networks.
Use Calculator →Wildcard Mask Calculator
Generate wildcard masks for Cisco ACLs and firewall rules. Essential for configuring access control lists and routing protocols.
Calculate Wildcard →IP Range to CIDR
Convert IP address ranges to CIDR notation instantly. Perfect for firewall rules, network documentation, and route aggregation.
Convert Range →What is My IP?
Discover your public IPv4 and IPv6 addresses instantly. See your ISP, location, and connection details in one place.
Check My IP →IP Whois Lookup
Look up ownership and registration details for any IP address. Find out which organization owns an IP block and contact information.
Lookup IP →Essential Subnetting Concepts
Master the fundamentals of IP subnetting with clear explanations and practical examples.
CIDR Notation
CIDR (Classless Inter-Domain Routing) notation uses a slash followed by the number of network bits. The higher the number, the smaller the network.
/25 = 128 IPs (126 usable)
/26 = 64 IPs (62 usable)
Subnet Mask
A 32-bit number that divides an IP address into network and host portions. 1s represent network bits, 0s represent host bits.
11111111.11111111.11111111.00000000
Network Address
The first address in a subnet that identifies the network itself. All host bits are set to 0. This address cannot be assigned to devices.
Network: 192.168.1.0
Broadcast Address
The last address in a subnet used to send data to all hosts. All host bits are set to 1. Reserved and cannot be assigned to devices.
Broadcast: 192.168.1.255
Wildcard Mask
The inverse of the subnet mask, used in Cisco ACLs and OSPF configurations. 0s match exactly, 1s match any value in that position.
Wildcard: 0.0.0.255
Private IP Ranges
Reserved IP ranges for internal networks (RFC 1918). These addresses are not routable on the public internet.
172.16.0.0/12 (Class B)
192.168.0.0/16 (Class C)
CIDR Subnet Reference Table
Common subnet sizes and their properties for quick network planning.
| CIDR | Subnet Mask | Wildcard Mask | Total IPs | Usable Hosts | Common Use |
|---|---|---|---|---|---|
| /30 | 255.255.255.252 | 0.0.0.3 | 4 | 2 | Point-to-Point Links |
| /29 | 255.255.255.248 | 0.0.0.7 | 8 | 6 | Small Server Clusters |
| /28 | 255.255.255.240 | 0.0.0.15 | 16 | 14 | Small Office Networks |
| /27 | 255.255.255.224 | 0.0.0.31 | 32 | 30 | Small Teams/VLANs |
| /26 | 255.255.255.192 | 0.0.0.63 | 64 | 62 | Medium Departments |
| /25 | 255.255.255.128 | 0.0.0.127 | 128 | 126 | Large Departments |
| /24 | 255.255.255.0 | 0.0.0.255 | 256 | 254 | Standard LAN/Home |
| /23 | 255.255.254.0 | 0.0.1.255 | 512 | 510 | Large Networks |
| /22 | 255.255.252.0 | 0.0.3.255 | 1,024 | 1,022 | Campus Networks |
| /16 | 255.255.0.0 | 0.0.255.255 | 65,536 | 65,534 | Enterprise Networks |
Powerful Features
Our subnet calculator tools are designed for accuracy, speed, and ease of use for networking professionals.
Instant Calculations
Get subnet results in milliseconds. No waiting, no page reloads required.
IPv4 & IPv6 Support
Full support for both IPv4 and IPv6 address calculations and conversions.
Cloud-Ready
Optimized for AWS VPC, Azure Virtual Networks, and GCP subnet planning.
Mobile Friendly
Works perfectly on any device — desktop, tablet, or smartphone.
100% Private
All calculations happen in your browser. Your data never leaves your device.
Educational
Shows binary representations and step-by-step breakdowns for learning.
100% Free
No registration, no fees, no limitations. Use all tools completely free.
Accurate Results
Trusted by network engineers worldwide. RFC-compliant calculations.
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