IP Subnet Calculator
Calculate every subnet detail from an IPv4 address and CIDR prefix in one go. Get the network and broadcast addresses, usable host range, wildcard and subnet masks - plus the binary breakdown, all computed instantly.
Enter a valid IPv4 address (four parts, each part 0–255). The result updates live when you change the prefix.
| Network Address | — |
|---|---|
| Broadcast Address | — |
| Netmask | — |
| Wildcard Mask | — |
| First Usable Host | — |
| Last Usable Host | — |
| Total Hosts | — |
| Usable Hosts | — |
| IP Class | — |
| Type | — |
Binary representation
| IP Address | — |
|---|---|
| Netmask | — |
How it works
The CIDR prefix tells how many of the first bits of the IP are the network part; the rest are for hosts. AND-ing the netmask with the IP gives the network address, and adding the wildcard (the mask's inverse) gives the broadcast. Normally usable hosts = total hosts − 2 (network and broadcast are reserved).
Example 1: 192.168.1.10/24 — network 192.168.1.0, broadcast 192.168.1.255, usable hosts 192.168.1.1 – 192.168.1.254, 254 usable in total.
Example 2: a /30 subnet has 4 addresses in total but only 2 usable — that is why /30 is commonly used for router-to-router links. /31 and /32 are special cases: this calculator shows usable hosts as 0 for them (the network/broadcast concept does not apply there / a /32 is a single host route).
How to use
- Type your IPv4 address in the address box (four parts, each 0 to 255).
- Pick the CIDR prefix / netmask from the dropdown — the result updates live.
- Read the network address, broadcast address, usable host range and masks.
- Check the binary representation and the worked examples for common cases like /24 and /30.
Tips
- The usable host count excludes the network and broadcast addresses - a /24 gives 254 usable hosts, not 256.
- Use the binary view to understand which bits belong to the network versus the host portion.
- For point-to-point links, a /31 (or /30) is enough; do not waste a whole /24 on two devices.
- Double-check the CIDR before configuring routers - one wrong digit can take a network offline.