Prefix length
A larger CIDR prefix creates a smaller network. Splitting a
/24 produces two /25 networks.
IPv4 / Network planning
Visualize IPv4 networks.
Shape every subnet.
Use this free visual IPv4 subnet calculator to turn a CIDR block into a clear network plan. Split, join, annotate, and share subnets without sending data to a server.
02 / Visualize
Address space
- Base network
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- Subnets
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- Total addresses
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- Usable addresses
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Allocation map
Width represents each subnet’s share of the base network.
Subnet plan
Select a color, add a note, or change the split at any level.
| Subnet | Address range | Usable range | Hosts | Note | Actions |
|---|
Your plan stays in this browser. Share links encode the design in the URL.
03 / Understand
IPv4 subnetting, at a glance.
Usable addresses
Standard IPv4 usually reserves network and broadcast addresses. Cloud providers reserve additional addresses in every subnet.
Plan visually
Split only where needed, label each allocation, and use color to distinguish environments, tiers, or ownership.