Enter an IPv4 address and choose a CIDR prefix. The tool calculates the network, broadcast, usable hosts, and wildcard mask. You can view binary representations, copy the summary, or download as a text file all done in your browser.
Free IP Subnet Calculator – no sign‑up
Calculate Subnet Details Instantly
Find network addresses, broadcast addresses, usable host ranges, subnet masks, and CIDR notation for any IPv4 subnet. Perfect for network engineers, IT professionals, and students — all free, private, and easy to use.
Master IP Subnetting with the IP Subnet Calculator
IP subnetting is a fundamental skill for network engineers, IT professionals, and students. It allows you to divide IP networks into smaller, more manageable subnets for better performance, security, and organization. This IP Subnet Calculator helps you quickly find critical subnet details: network address, broadcast address, usable host range, subnet mask, CIDR notation, and total addresses. Enter any IPv4 address and CIDR prefix length, and get instant results. Perfect for network design, troubleshooting, and certification studies. All calculations are local, so your data stays private.
What Is an IP Subnet Calculator?
An IP subnet calculator is a tool that computes key subnet details from an IP address and subnet mask. It provides:
- Network Address: The starting address of the subnet.
- Broadcast Address: The last address in the subnet.
- Usable Host Range: The range of addresses that can be assigned to devices.
- Subnet Mask: The subnet mask in both dotted-decimal and CIDR notation.
- Total Addresses: The total number of addresses in the subnet.
- Usable Hosts: The number of usable addresses (total minus network and broadcast).
It’s essential for network design, configuration, and troubleshooting.
How to Use the IP Subnet Calculator
Enter IP Address
Type the IPv4 address (e.g., 192.168.1.0).
Enter Subnet Mask
Enter the CIDR prefix length (e.g., /24) or subnet mask (e.g., 255.255.255.0).
Get Results
Instantly see network address, broadcast, usable range, and all subnet details.
How Subnet Is Computed
The calculator uses these standard networking formulas:
- Network Address: IP & Subnet Mask (bitwise AND).
- Broadcast Address: Network Address | ~Subnet Mask.
- Usable Range: Network + 1 to Broadcast − 1.
- Total Addresses: 2^(32−CIDR).
- Usable Hosts: Total Addresses − 2.
The calculator supports all IPv4 subnet masks from /0 to /32.
Key Subnet Formulas
Network = IP & Mask
Broadcast = Network | ~Mask
Total Hosts = 2^(32−CIDR)
Usable Hosts = Total Hosts − 2
Key Features of This IP Subnet Calculator
Complete Subnet Details
Network, broadcast, usable range, and more.
CIDR & Dotted‑Decimal
Supports both formats for subnet masks.
Binary Representation
See the binary format for network and mask.
Private & Secure
All calculations are local — your data never leaves your device.
Benefits of Using an IP Subnet Calculator
- ✅ Quick and accurate – no manual calculations needed.
- ✅ Educational – understand binary and subnetting.
- ✅ Time-saving – ideal for network design and troubleshooting.
- ✅ Certification prep – practice for CCNA, Network+, and other exams.
- ✅ Ideal for network engineers, IT professionals, and students – anyone working with IP networks.
Common Subnet Masks
/24
255.255.255.0, 256 addresses, 254 hosts (Class C)
/16
255.255.0.0, 65,536 addresses, 65,534 hosts (Class B)
/8
255.0.0.0, 16,777,216 addresses, 16,777,214 hosts (Class A)
/25
255.255.255.128, 128 addresses, 126 hosts
/26
255.255.255.192, 64 addresses, 62 hosts
/27
255.255.255.224, 32 addresses, 30 hosts
/28
255.255.255.240, 16 addresses, 14 hosts
/29
255.255.255.248, 8 addresses, 6 hosts
Real‑World Applications of Subnet Calculations
- 🏢 Network Design: Planning IP address allocation for networks.
- 🛠️ Troubleshooting: Diagnosing network connectivity issues.
- 🔒 Security: Segregating networks for better security.
- 📚 Certification: Preparing for CCNA, Network+, and other exams.
- 🌍 ISP Operations: Allocating IP blocks to customers.
How to Interpret Your Results
Network Address
The first address in the subnet, used to identify the network.
Broadcast Address
The last address in the subnet, used for broadcasting to all hosts.
Usable Host Range
The addresses that can be assigned to network devices (excluding network and broadcast).
Step‑by‑Step Example
The calculator shows the binary calculation, network address, broadcast, and usable range with step‑by‑step explanations.
Understanding CIDR Notation
- CIDR (Classless Inter-Domain Routing): A method for allocating IP addresses and routing.
- Prefix Length: The number of bits in the subnet mask (e.g., /24 = 24 bits).
- Example: 192.168.1.0/24 means subnet mask 255.255.255.0.
Factors That Affect Subnet Results
- 🔢 IP address entered
- 📊 Subnet mask/CIDR prefix
- 🧮 Binary calculations
- 📈 Network class (A, B, C)
- 📉 Subnet mask validity
- 📋 IPv4 vs. IPv6 (IPv4 only)
Detailed Worked Example
Scenario: IP address 192.168.1.0 with subnet mask /24 (255.255.255.0).
- ✅ Step 1: IP: 11000000.10101000.00000001.00000000
- ✅ Step 2: Mask: 11111111.11111111.11111111.00000000
- ✅ Step 3: Network = IP & Mask = 192.168.1.0
- ✅ Step 4: Broadcast = Network | ~Mask = 192.168.1.255
- ✅ Step 5: Usable Range = 192.168.1.1 to 192.168.1.254
- ✅ Step 6: Total Addresses = 256, Usable Hosts = 254
- ✅ Result: Network: 192.168.1.0, Broadcast: 192.168.1.255, Usable: 192.168.1.1 – 192.168.1.254
Who Can Use This IP Subnet Calculator?
- 🌐 Network Engineers – designing and managing IP networks.
- 🛠️ IT Professionals – troubleshooting network issues.
- 🎓 Students – learning networking concepts.
- 📚 Certification Candidates – preparing for CCNA, Network+.
- 🔧 System Administrators – configuring network devices.
Key Subnet Terms
- Subnet
- A logical subdivision of an IP network.
- CIDR
- Classless Inter-Domain Routing – a method for IP address allocation.
- Network Address
- The first address in a subnet, identifying the network.
- Broadcast Address
- The last address in a subnet, used for sending to all hosts.
Tips for Using the IP Subnet Calculator
- Ensure the IP address is a valid IPv4 address.
- The CIDR prefix must be between 0 and 32.
- For classful subnetting, remember default masks: /8 (A), /16 (B), /24 (C).
- Use the binary view to understand how subnetting works.
- Check that your subnet has enough usable hosts for your needs.
Advantages of This IP Subnet Calculator
- ✅ 100% free – no sign‑up, no ads
- ✅ Supports all CIDR prefixes (0-32)
- ✅ Binary representation for learning
- ✅ Step‑by‑step explanations
- ✅ Private – no data leaves your device
Limitations of This Calculator
The calculator supports IPv4 addresses only. It does not support IPv6 subnetting. For IPv6, use a specialized IPv6 subnet calculator.
Accuracy of Results
Using precise binary arithmetic, results are accurate for all valid IPv4 addresses and subnet masks. Calculations follow standard networking formulas.
Security and Privacy
Your data is not stored or transmitted. All calculations are performed locally in your browser.
Mobile‑Friendly Design
Fully responsive and optimized for all screen sizes.
Frequently Asked Questions
How do I calculate subnet details from an IP address?
Enter the IP address and subnet mask (or CIDR prefix). The calculator will compute network address, broadcast address, usable range, and more.
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation represents the subnet mask as a prefix length (e.g., /24 for 255.255.255.0).
How many usable hosts are in a subnet?
Total addresses in subnet minus 2 (network address and broadcast address). For /24, usable hosts = 256 – 2 = 254.
What is the difference between network and broadcast address?
The network address identifies the subnet. The broadcast address sends data to all devices on the subnet.
Is my data safe?
Absolutely. Your data is never stored or transmitted; everything stays in your browser.
Does this calculator support IPv6?
No, this calculator is for IPv4 only. For IPv6 subnetting, use a specialized IPv6 calculator.
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Conclusion: Design Networks with Confidence
IP subnetting is essential for modern networking. This IP Subnet Calculator gives you instant, accurate subnet details with clear explanations. Try it now and simplify your network calculations.
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