Subnet Calculator (IPv4 CIDR)

Find the network, broadcast, host range, mask and host count for any IPv4 address and prefix.

IP address and prefix

CIDR (192.168.1.10/24) or an address and mask (10.0.0.5 255.255.255.0).

Result

Network

192.168.1.0/24

Usable host range: 192.168.1.1 – 192.168.1.254
Broadcast: 192.168.1.255
Subnet mask: 255.255.255.0
Wildcard mask: 0.0.0.255
Usable hosts: 254
Total addresses: 256
Class and scope: Class C · Private (RFC 1918)
Mask in binary: 11111111.11111111.11111111.00000000

Runs in your browser — nothing you enter is sent to a server.

How the Subnet Calculator (IPv4 CIDR) works

Type an IPv4 address with its prefix length (CIDR notation such as 192.168.1.10/24) or with a subnet mask. The calculator masks the address to find the network, sets the host bits to find the broadcast address, and lists the usable host range, the mask and wildcard mask, and the number of hosts. It also tells you whether the address is private, public or special.

Formulas

Network and broadcast

network = address AND mask, broadcast = network OR NOT mask

Hosts

usable hosts = 2^{32 − prefix} − 2

/31 point-to-point links have 2 usable addresses and /32 a single host (RFC 3021).

Examples

192.168.1.10/24

Network 192.168.1.0, broadcast 192.168.1.255, hosts 192.168.1.1–192.168.1.254 (254 usable), mask 255.255.255.0.

10.20.30.40 with mask 255.255.240.0

That's a /20: network 10.20.16.0, broadcast 10.20.31.255 and 4,094 usable hosts.

Frequently asked questions

What does /24 mean?

The first 24 of the 32 bits identify the network; the remaining 8 number the hosts.

Which addresses are private?

10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16 (RFC 1918) — used inside home and office networks.

Does it support IPv6?

This calculator is IPv4; the IP Address Converter expands and compresses IPv6 addresses.

IP Address Converter

Convert IPv4 addresses between dotted, integer, hex and binary, and expand or compress IPv6.

Network Tools

MAC Address Formatter

Reformat a MAC address with colons, hyphens or Cisco dots, and see whether it's multicast or locally administered.