The CIDR prefix length: the number of leading bits fixed as the network part. /24 means a 255.255.255.0 mask — 256 addresses, of which 254 are usable hosts (network and broadcast addresses are reserved).

How many hosts fit in a subnet?

2^(32 − prefix) − 2 for IPv4. A /26 has 64 addresses and 62 usable hosts; a /30 point-to-point link has just 2 usable hosts.

What are the private IPv4 ranges?

10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 (RFC 1918). These are never routed on the public internet and are free to use in local networks.

IP Subnet Calculator

Enter an IPv4 address with a CIDR prefix (like 192.168.1.0/24) to get the complete subnet picture: network address, broadcast address, first and last usable host, subnet mask, wildcard mask, and the number of usable hosts. Ideal for network planning, firewall rules, and studying for networking certifications.

Developer Tools

IPv4 address

CIDR prefix

Network address: 192.168.1.0/24
Subnet mask: 255.255.255.0
Wildcard mask: 0.0.0.255
Broadcast address: 192.168.1.255
Usable host range: 192.168.1.1 – 192.168.1.254
Total addresses: 256
Usable hosts: 254

Private by default

This tool runs entirely in your browser. Your data is never uploaded to a server.

How to use

3 clear steps.

Enter an IPv4 address (e.g. 192.168.1.10).
Set the CIDR prefix length with the selector (e.g. /24).
Read the network, broadcast, host range, and mask details.

Good to know

Frequently asked questions

What does /24 mean?: The CIDR prefix length: the number of leading bits fixed as the network part. /24 means a 255.255.255.0 mask — 256 addresses, of which 254 are usable hosts (network and broadcast addresses are reserved).
How many hosts fit in a subnet?: 2^(32 − prefix) − 2 for IPv4. A /26 has 64 addresses and 62 usable hosts; a /30 point-to-point link has just 2 usable hosts.
What are the private IPv4 ranges?: 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 (RFC 1918). These are never routed on the public internet and are free to use in local networks.