Professional IP Subnet Calculator for Network Engineers
Our IP Calculator helps network administrators, IT professionals, and students quickly calculate subnet masks, network addresses, broadcast addresses, and usable host ranges using CIDR notation (/1–/32). Whether you are designing enterprise networks, configuring routers, or planning cloud infrastructure, accurate subnetting is essential for performance and security.
This tool simplifies complex subnet calculations by instantly generating key IPv4 networking details including wildcard masks, IP classes, and host capacity. It is ideal for CCNA training, network troubleshooting, firewall configuration, and ISP planning.
With built-in PDF reporting, you can export professional subnet analysis reports for documentation, audits, or client presentations — saving time and reducing manual errors.
Table of Contents
Why Use This Subnet Calculator?
- Instantly calculate subnet network information using CIDR
- Understand IP addressing and network segmentation
- Improve routing efficiency and IP utilization
- Generate downloadable subnet analysis reports
- Ideal for network engineers, system admins, and students
Whether you are planning LANs, WANs, VPNs, or cloud networks, proper subnetting helps reduce broadcast traffic and improves scalability.
Who Should Use This Tool?
This calculator is designed for:
- Network Engineers & Administrators
- Cybersecurity Professionals
- Cloud Infrastructure Engineers
- ISP & Telecom Technicians
- CCNA / CCNP Students
- Hosting & Server Managers
If you work with routers, firewalls, enterprise switches, or cloud networking platforms, this tool can speed up your workflow.
IPv4 Subnet Reference Table (CIDR, Masks & Classes)
Below is a reference table showing common IPv4 subnet sizes, network masks, usable hosts per subnet, and default IP class ranges.
| Prefix (CIDR) | Network Mask | Usable Hosts | Default Class |
|---|---|---|---|
| /1 | 128.0.0.0 | 2,147,483,646 | Supernet (Large Aggregation) |
| /2 | 192.0.0.0 | 1,073,741,822 | Supernet |
| /3 | 224.0.0.0 | 536,870,910 | Supernet |
| /4 | 240.0.0.0 | 268,435,454 | Supernet |
| /5 | 248.0.0.0 | 134,217,726 | Supernet |
| /6 | 252.0.0.0 | 67,108,862 | Supernet |
| /7 | 254.0.0.0 | 33,554,430 | Supernet |
| /8 | 255.0.0.0 | 16,777,214 | Class A (1.0.0.0 – 126.255.255.255) |
| /9 | 255.128.0.0 | 8,388,606 | Class A |
| /10 | 255.192.0.0 | 4,194,302 | Class A |
| /11 | 255.224.0.0 | 2,097,150 | Class A |
| /12 | 255.240.0.0 | 1,048,574 | Class A |
| /13 | 255.248.0.0 | 524,286 | Class A |
| /14 | 255.252.0.0 | 262,142 | Class A |
| /15 | 255.254.0.0 | 131,070 | Class A |
| /16 | 255.255.0.0 | 65,534 | Class B (128.0.0.0 – 191.255.255.255) |
| /17 | 255.255.128.0 | 32,766 | Class B |
| /18 | 255.255.192.0 | 16,382 | Class B |
| /19 | 255.255.224.0 | 8,190 | Class B |
| /20 | 255.255.240.0 | 4,094 | Class B |
| /21 | 255.255.248.0 | 2,046 | Class B |
| /22 | 255.255.252.0 | 1,022 | Class B |
| /23 | 255.255.254.0 | 510 | Class B |
| /24 | 255.255.255.0 | 254 | Class C (192.0.0.0 – 223.255.255.255) |
| /25 | 255.255.255.128 | 126 | Class C |
| /26 | 255.255.255.192 | 62 | Class C |
| /27 | 255.255.255.224 | 30 | Class C |
| /28 | 255.255.255.240 | 14 | Class C |
| /29 | 255.255.255.248 | 6 | Class C |
| /30 | 255.255.255.252 | 2 | Class C (Point-to-Point) |
| /31 | 255.255.255.254 | 0 | Special (RFC 3021) |
| /32 | 255.255.255.255 | 0 | Single Host Route |
Related Networking Tools
Use this IP Subnet Calculator together with bandwidth estimation, IP planning, and network design tools to optimize enterprise internet performance.
FAQs on IP Calculator
What is an IP Subnet Calculator?
An IP Subnet Calculator is a networking tool that helps you divide IP address ranges into smaller subnetworks. It calculates subnet masks, network IDs, broadcast addresses, and usable host ranges automatically.
Why is subnetting important in networking?
Subnetting improves network performance, security, and scalability by reducing broadcast traffic and organizing IP address allocation efficiently. It is essential for enterprise networks, cloud systems, and ISP infrastructure.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) is a method used to define subnet sizes using prefixes like /24, /16, or /30. It replaces traditional class-based networking and allows flexible IP allocation.
How many usable hosts can a subnet have?
The number of usable hosts depends on the CIDR value. For example:
/24 → 254 usable hosts
/30 → 2 usable hosts
/16 → 65,534 usable hosts
The calculator instantly determines usable host counts for any subnet.
What is the difference between subnet mask and wildcard mask?
A subnet mask defines the network portion of an IP address, while a wildcard mask is the inverse and is commonly used in router ACL configurations.
Can this tool be used for CCNA exam preparation?
Yes. This subnet calculator is very useful for CCNA and networking students because it helps visualize subnetting results and understand IP addressing concepts faster.
Is this subnet calculator free to use?
Yes, the tool is completely free and works directly in your browser without requiring any installation.
IP Subnet Calculator
Enter an IPv4 address and CIDR to calculate subnet mask, network address, broadcast address, usable hosts, and IP class. Download a detailed PDF report.