Plan your network IP allocation by entering a base network in CIDR notation and defining subnets with the number of hosts needed and a usage label. The planner calculates optimal subnet sizes and assigns non-overlapping address ranges. All calculations run locally in your browser.
IP address planning is the process of designing a structured allocation scheme for your network's IP address space. A well-designed plan ensures efficient use of addresses, simplifies routing, enables proper security segmentation, and makes future growth manageable. Whether you're setting up a small office network or designing an enterprise campus, planning your IP allocation before deployment prevents costly restructuring later.
Effective IP planning requires understanding subnetting, CIDR notation, and how different network segments interact. Your plan should account for current needs plus anticipated growth, typically allocating only 50-60% of available space initially. If you're working with private address ranges, our Private IP Reference can help you choose the right base network.
The first step in IP planning is selecting an appropriate base network from the RFC 1918 private ranges. The choice depends on your organization's size and growth expectations:
| Private Range | CIDR | Total Addresses | Best For |
|---|---|---|---|
| 10.0.0.0/8 | /8 | 16,777,216 | Large enterprise, multi-site (thousands of subnets) |
| 172.16.0.0/12 | /12 | 1,048,576 | Medium enterprise, data centers |
| 192.168.0.0/16 | /16 | 65,536 | Small business, home networks, labs |
Most home networks default to 192.168.1.0/24 (accessible at 192.168.1.1) or 10.0.0.0/24 (at 10.0.0.1). For larger deployments, starting with a 10.0.0.0/16 or even 10.0.0.0/8 gives maximum flexibility. Use our IP Range Calculator to visualize the address space available in each range.
Pro Tip: When planning a multi-site network, assign each site a contiguous block that can be summarized into a single route. For example, give Site A 10.1.0.0/16, Site B 10.2.0.0/16, and Site C 10.3.0.0/16. This enables route summarization at the WAN boundary, keeping routing tables small and efficient. Use our CIDR Converter to verify your summary routes.
Each subnet should be sized based on the number of devices it will contain, plus room for growth. The planner above automatically selects the smallest subnet that fits your requested host count. Here's a reference for common subnet sizes:
| Prefix | Subnet Mask | Total IPs | Usable Hosts | Common Use |
|---|---|---|---|---|
| /30 | 255.255.255.252 | 4 | 2 | Point-to-point WAN links |
| /28 | 255.255.255.240 | 16 | 14 | Small server VLAN, management |
| /27 | 255.255.255.224 | 32 | 30 | Small office, conference room |
| /26 | 255.255.255.192 | 64 | 62 | Department, floor segment |
| /25 | 255.255.255.128 | 128 | 126 | Large department |
| /24 | 255.255.255.0 | 256 | 254 | Standard VLAN, most common |
| /23 | 255.255.254.0 | 512 | 510 | Large floor, building wing |
| /22 | 255.255.252.0 | 1,024 | 1,022 | Building, campus segment |
For a deeper understanding of how subnet masks work, check our guide on what is a subnet mask. You can also use the Subnet Calculator to calculate individual subnets in detail.
Good IP planning goes hand-in-hand with network segmentation. Separating different types of traffic into distinct subnets improves security, performance, and manageability. A typical network should include these segments:
Each segment should have its own subnet with appropriate firewall rules between them. Verify your firewall is properly configured by checking open ports between segments.
Consistent addressing conventions make networks easier to manage and troubleshoot. Establish these conventions before deploying and document them:
# Example addressing convention for 10.0.0.0/16 network:
# .1 = Default gateway (router interface)
# .2-.10 = Network infrastructure (switches, APs)
# .11-.20 = Servers (DHCP reservations)
# .21-.49 = Printers, IoT, static devices
# .50-.200 = DHCP pool for dynamic clients
# .201-.254 = Reserved for future use
# Example multi-site allocation:
# 10.1.0.0/16 = Headquarters
# 10.2.0.0/16 = Branch Office A
# 10.3.0.0/16 = Branch Office B
# 10.4.0.0/16 = Data Center
# 10.10.0.0/16 = VPN usersWhen setting up DHCP for each subnet, ensure the pool aligns with your static allocation ranges to prevent IP address conflicts. For devices that need consistent addresses (servers, printers), use either static IP configuration or DHCP reservations.
A plan is only useful if it's documented and maintained. Your documentation should include:
This tool generates the allocation table portion of your documentation. For detailed information about each subnet, use the Subnet Calculator. To verify address ranges don't overlap, check them with the IP Range Calculator.
For a small office (under 200 devices), 192.168.0.0/16 provides 65,534 usable addresses — more than enough. Start with a /24 subnet (192.168.1.0/24) for your main network, accessible at 192.168.1.1, and create additional /24 subnets for guests and servers as needed.
Larger subnets have stricter alignment requirements — a /24 must start on a 256-address boundary, a /23 on a 512-address boundary. Allocating the largest subnets first ensures proper alignment without wasting address space. The planner above handles this automatically.
A common guideline is to allocate only 50-60% of your available address space initially, leaving 40-50% for growth. For individual subnets, size them for 2x your current device count. It's much easier to allocate larger subnets upfront than to re-address an active network later.
VLSM (Variable Length Subnet Masking) allows you to use different subnet sizes within the same network. Without VLSM, every subnet must be the same size. VLSM is what makes efficient IP planning possible — you can have a /30 for a point-to-point link and a /24 for a user VLAN within the same address block.
Use 10.0.0.0/8 for larger networks that need many subnets or sites. Use 192.168.0.0/16 for simpler networks. Avoid 172.16.0.0/12 unless you have a specific reason, as it's less commonly used and can cause confusion. Whatever you choose, document it and be consistent.
Maintain a central IP address plan (like the one this tool generates), use DHCP for most devices, reserve static ranges clearly, and never manually assign IPs within the DHCP pool range. If conflicts occur, see our guide on fixing IP address conflicts.
This planner is designed for IPv4 subnetting. IPv6 uses a different allocation approach — the standard practice is to assign /64 subnets to every link and use /48 or /56 prefixes per site. IPv6's vast address space makes conservation less of a concern, but structured planning is still important for manageability.
About Tommy N.
Tommy is the founder of RouterHax and a network engineer with 10+ years of experience in home and enterprise networking. He specializes in router configuration, WiFi optimization, and network security. When not writing guides, he's testing the latest mesh WiFi systems and helping readers troubleshoot their home networks.
 |
 |
 |
 |
Promotion for FREE Gifts. Moreover, Free Items here. Disable Ad Blocker to get them all.
Once done, hit any button as below
|
|
|
|