What is IP Subnet Planner?

Free online ip subnet planner calculator for other calculations. Get accurate results instantly with our professional-grade calculation tools.

How accurate is the IP Subnet Planner?

The IP Subnet Planner provides accurate calculations based on standard formulas and algorithms. Results are for informational purposes only and should not replace professional advice.

Is the IP Subnet Planner free to use?

Yes, all calculators on CalcBucket are completely free to use with no registration required.

IP Subnet Planner

Plan, organize, allocate, and annotate subnets within an aggregate. Then, share for review or directly export subnet allocations into a file

How to Use This IP Subnet Planner

Our IP Subnet Planner supports both IPv4 and IPv6 subnet planning, making it the perfect tool for modern network administrators. Whether you're setting up a small office network or planning a large-scale infrastructure with dual-stack support, this tool makes subnet planning simple and comprehensive.

1. Choose IP Version

Select between IPv4 or IPv6 for your subnet planning. Switch between versions seamlessly.

2. Enter Subnet Details

Enter your IP address and choose the prefix length. For IPv6, choose between short or full notation display.

3. Calculate & Plan

Get comprehensive subnet details including network address, broadcast address, and usable host range.

4. Split & Join Subnets

Divide subnets into smaller parts or combine them back together for flexible network management.

IPv4 Example

Planning a small office network? Start with 192.168.1.0/24 (256 addresses) and split it into smaller subnets for different departments. IT gets 192.168.1.0/26 (64 addresses), Marketing gets 192.168.1.64/26 (64 addresses), and Guest WiFi gets 192.168.1.128/26 (64 addresses).

IPv6 Example

Planning a modern dual-stack network? Use 2001:db8::/64 for your main network and split it into /72 subnets for departments. IT gets 2001:db8::/72, Marketing gets 2001:db8:0:1::/72, and Guest WiFi gets 2001:db8:0:2::/72. Each /72 subnet provides 2^56 addresses!

What is IP Subnet Planning?

Simple Explanation

IP subnet planning is like dividing a large building into different floors and rooms. Instead of having one big network where all devices can talk to each other, you create smaller, organized networks called subnets. This makes your network more secure, easier to manage, and helps you use IP addresses more efficiently. With IPv6 adoption growing rapidly, modern subnet planning often involves dual-stack configurations supporting both IPv4 and IPv6.

Example: Instead of putting all 500 office computers on one big network, you might create separate subnets for IT (50 computers), Sales (100 computers), and Guest WiFi (50 computers). With IPv6, you can also plan for future growth with virtually unlimited address space.

Why We Built This Tool

We got tired of subnet planning tools that are overly complicated, require you to sign up, or don't support both IPv4 and IPv6. So we built this comprehensive tool that lets you plan your network subnets for both IP versions without any hassle.

Whether you're setting up a small office network with IPv4, planning a large-scale IPv6 deployment, or designing a dual-stack infrastructure, this tool helps you figure out how to divide your IP addresses efficiently. No registration, no hidden costs, just a free tool that works with both IPv4 and IPv6.

IPv4 vs IPv6 Subnetting: Understanding the Differences

IPv4 Subnetting

Address Space: 32-bit addresses (4.3 billion total)
Notation: Dotted decimal (192.168.1.0/24)
Subnet Masks: 255.255.255.0 or /24
Common Sizes: /24 (256), /26 (64), /28 (16)
Private Ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16
Use Case: Legacy networks, small to medium businesses

IPv6 Subnetting

Address Space: 128-bit addresses (340 undecillion total)
Notation: Hexadecimal (2001:db8::/64)
Prefix Length: /64 is standard for most subnets
Common Sizes: /64 (standard), /72, /80 for smaller segments
Private Ranges: fc00::/7 (ULA), fe80::/10 (link-local)
Use Case: Modern networks, IoT, future-proofing

Dual-Stack Planning

Many modern networks run both IPv4 and IPv6 simultaneously (dual-stack). Our tool helps you plan both address families, ensuring your network can communicate with both legacy IPv4 systems and modern IPv6-enabled devices.

Pro Tip: When planning dual-stack networks, design your IPv6 subnets to align with your IPv4 subnet boundaries for easier management and troubleshooting.

How Our Tool Helps You

Dual-Stack Support

Plan both IPv4 and IPv6 subnets with seamless switching between IP versions. Perfect for modern networks transitioning to IPv6.

Example: Switch between 192.168.1.0/24 and 2001:db8::/64

Split Subnets

Divide large subnets into smaller parts for both IPv4 and IPv6. Perfect when you need separate networks for different departments.

Example: Split IPv4 192.168.1.0/24 into /26 subnets or IPv6 2001:db8::/64 into /72 subnets

Join Subnets

Combine smaller subnets back into larger ones for both IP versions. Useful when you need more addresses in a single network.

Example: Join two IPv4 /26 subnets into one /25 subnet

IPv6 Notation Options

Choose between short and full IPv6 notation display. Short notation compresses zeros (2001:db8::1) while full notation shows all segments.

Example: 2001:db8::1 (short) vs 2001:0db8:0000:0000:0000:0000:0000:0001 (full)

Calculate Details

Get comprehensive subnet information for both IPv4 and IPv6 - network address, broadcast address, and usable host range.

Example: See exactly how many devices can connect to your subnet

Common Questions

Is this tool really free?

Yes, completely free. No registration, no hidden fees, no premium versions. Just open the tool and start planning your subnets.

How accurate are the calculations?

We use the same formulas that network professionals use. Our calculations follow standard networking principles that you can verify with other sources.

Do you store my network data?

No. All calculations happen in your browser. We never see your IP addresses or network information. Your privacy is completely protected.

Can I use this for work or school?

Absolutely. Many people use our tool for work projects, school assignments, and business decisions. Just remember to double-check important calculations with other sources when needed.

What's the difference between splitting and joining subnets?

Splitting divides a large subnet into smaller parts (like cutting a pie into slices). Joining combines smaller subnets back into larger ones (like putting the slices back together). Both help you organize your network efficiently and work with both IPv4 and IPv6.

Why should I use IPv6 for subnet planning?

IPv6 provides virtually unlimited address space (340 undecillion addresses), eliminates the need for NAT, and offers better security features. It's essential for future-proofing your network and supporting IoT devices, mobile networks, and modern applications.

What's the difference between IPv4 and IPv6 subnetting?

IPv4 uses 32-bit addresses with subnet masks (like /24), while IPv6 uses 128-bit addresses with prefix lengths (like /64). IPv6 typically uses /64 as the standard subnet size, providing 2^64 addresses per subnet. IPv6 also has different private address ranges and notation.

Can I plan both IPv4 and IPv6 subnets together?

Yes! Our tool supports dual-stack planning, allowing you to design both IPv4 and IPv6 subnets for the same network infrastructure. This is essential for modern networks that need to support both legacy IPv4 systems and new IPv6-enabled devices.

Important Note

This tool is for planning purposes only. For important network decisions, please consult with qualified network professionals.

Network configurations are estimates only
Always test designs in non-production environments
Verify calculations with other sources when needed