Subnet Calculator
Calculate IP ranges, network addresses, and subnet information
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Network Address
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Broadcast Address
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First Host
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Last Host
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Subnet Mask
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Wildcard Mask
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Total Hosts
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Usable Hosts
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CIDR Notation
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IP Class
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Binary Subnet Mask
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IP Range
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Frequently Asked Questions
How to plan subnet allocation?
Start with your total IP range, determine subnets needed, calculate required sizes, and allocate non-overlapping ranges.
What is VLSM?
Variable Length Subnet Masking allows subnets of different sizes within the same network for efficient IP use.
Why use a visual subnet calculator?
Visual tools help see IP allocation at a glance, avoid overlaps, identify unused space, and plan growth.
What are the reserved addresses in every subnet?
Every subnet reserves two addresses: the network address (first IP, all host bits zero) and the broadcast address (last IP, all host bits one). These cannot be assigned to devices.
Can two devices on different subnets communicate directly?
No. Devices on different subnets need a router or Layer 3 switch to forward traffic between them. The router acts as the default gateway for each subnet.
Common CIDR Blocks
| CIDR | Subnet Mask | Hosts | Use Case |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 | Large ISP |
| /16 | 255.255.0.0 | 65,534 | Large Enterprise |
| /24 | 255.255.255.0 | 254 | Small Network |
| /28 | 255.255.255.240 | 14 | Small Office |
| /30 | 255.255.255.252 | 2 | Point-to-Point |