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IPv4 subnet calculator

Enter an address and CIDR — get the network, broadcast, mask, host range and usable count instantly. Everything client-side.

Quick reference

CIDR notation (e.g. /24) sets how many bits are the network vs hosts. A /24 gives 256 addresses (254 usable); /30 gives 4 (2 usable, common for point-to-point links). Running your own server? Every KVM VPS from us gives you full root to configure networking, firewalls and routes as you like.

FAQ

Straight answers.

What does /24 mean?

The first 24 bits are the network; the last 8 are hosts — 256 total addresses, 254 usable (network + broadcast are reserved).

How many usable hosts in a subnet?

Total addresses minus 2 (network + broadcast), except /31 (2, point-to-point) and /32 (1, single host).

What's the wildcard mask?

The inverse of the netmask — used by some routers/ACLs (e.g. Cisco). 0.0.0.255 is the wildcard for a /24.

Is this IPv6?

This calculator is IPv4. IPv6 subnetting works on 128 bits and is usually delegated in /64s.

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