Subnet Calculator
Enter an IP address and CIDR prefix to calculate subnet mask, network address, broadcast address, first/last usable hosts, and total host count.
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Why use a Subnet Calculator?
Subnetting is a fundamental networking skill — whether you're designing cloud VPCs, configuring firewalls, or planning office LANs. Manually computing network address, broadcast address, host ranges, and wildcard masks is error-prone. This calculator does it instantly from any IP/CIDR combination and can also split your network into equal subnets. Explore more in the networking tools category alongside IP lookup and DNS lookup.
Full subnet breakdown
Network address, broadcast, first/last host, host count, subnet mask, and wildcard mask — all in one calculation.
Subnet splitting
Divide any network into 2, 4, 8, or 16 equal subnets and see the full breakdown for each.
CIDR ↔ mask
Enter a CIDR prefix (/24) or type a subnet mask (255.255.255.0) — both inputs are supported and stay in sync.
Common CIDR subnets reference
These are the most frequently used CIDR blocks in cloud networking, office LANs, and data centres.
| CIDR | Subnet mask | Usable hosts | Typical use |
|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 | Class A private range (10.0.0.0/8) |
| /16 | 255.255.0.0 | 65,534 | Large VPCs, corporate WAN segments |
| /24 | 255.255.255.0 | 254 | Small office LAN, cloud subnet, DMZ |
| /28 | 255.255.255.240 | 14 | Small cloud subnet for load balancers or NAT gateways |
| /30 | 255.255.255.252 | 2 | Point-to-point links (router interconnects) |