Network Planner
Plan and organize your network subnets with ease
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Add your first subnet to start organizing your network address space.
Your plan is saved automatically in this browser only. Use Export Plan to back it up or share it with your team.
How to plan your network
- Click Add Subnet and give the subnet a descriptive name, such as NYC – Voice VLAN 20.
- Choose IPv4 or IPv6, then enter the network address and prefix length.
- Add a description for anything the next admin should know — owner, purpose, or VLAN ID.
- Repeat for each subnet. The planner validates every entry and flags overlaps as you go.
- Export the finished plan as JSON to back it up or share it.
Tips for a clean IP addressing plan
- Plan hierarchically. Give each site or region a large block and carve subnets from it, so related subnets stay together and routes can be summarized.
- Leave room to grow. Size subnets for where you'll be in two to three years, not just today. The IPv4 Subnet Calculator shows host counts for any prefix.
- Separate by function. Keep users, voice, servers, IoT, and guest traffic in their own subnets.
- Use consistent names. Including the site and VLAN in every subnet name makes the plan easy to search. See our guide to naming conventions.
- Avoid default ranges. 192.168.0.0/24 and 192.168.1.0/24 are the most likely to collide with home networks and acquired offices.
Managing several locations? Read our guide to multi-site IP address management, and see best practices for subnet planning in enterprise networks.
Frequently Asked Questions
Where is my network plan stored?
Your plan is saved in your browser's local storage on this device. Nothing is sent to our servers. Use Export Plan to download a JSON backup or to move the plan to another computer.
How does overlap detection work?
Every time you add or edit a subnet, the planner compares its address range with every other subnet of the same IP version. Overlapping subnets are highlighted and counted, and you are warned before saving a subnet that overlaps an existing one.
Why does the planner say "host bits are set"?
A subnet must start on its network address. For example, 192.168.1.10/24 is a host inside the 192.168.1.0/24 network, not a network itself. The planner suggests the correct network address so you can fix it with one edit.
Can I share a network plan with my team?
Yes. Export the plan as JSON and send it to a teammate, who can load it with Import Plan. For a shared plan that stays in sync automatically, with real-time updates and network scanning, create a free Subnet24 account.
Does the Network Planner support IPv6?
Yes. Choose IPv6 as the IP version and enter a network address and prefix length, such as 2001:db8:10::/64. IPv4 and IPv6 subnets are counted separately and only compared with subnets of the same version.
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