IPv4 Subnet Calculator
Enter an IP address and CIDR prefix to calculate the network, broadcast, mask, and usable host range.
- Network Address
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- Broadcast Address
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- Subnet Mask
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- Wildcard Mask
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- Usable Host Range
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- Usable Hosts
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Understanding Subnets & CIDR
A subnet divides a larger network into smaller, manageable pieces. CIDR (Classless Inter-Domain Routing) notation like /24 describes how many bits of an IP address identify the network versus individual hosts.
Common CIDR blocks
/24— 256 addresses, 254 usable hosts (a typical small LAN)./16— 65,536 addresses (a large private network)./30— 4 addresses, 2 usable (point-to-point links).
Subnet planning matters when configuring firewalls, VPCs, and routing on your VPS or dedicated server.