Network & IP
IPv4 Subnet / CIDR Calculator
Calculate network range, subnet mask, broadcast address and usable host count from CIDR notation.
Private address range
- 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
- First host
- 192.168.1.1
- Last host
- 192.168.1.254
- Total addresses
- 256
- Usable hosts
- 254
- Mask in binary
- 11111111.11111111.11111111.00000000
What is IPv4 Subnet / CIDR Calculator?
CIDR notation such as 192.168.1.0/24 packs two facts into one string: a starting address, and how many leading bits belong to the network portion. The number after the slash tells you how many bits are fixed — the larger it is, the smaller the network. From that you can derive the full address range, the mask, the broadcast address and how many machines fit.
This calculator works all of that out for you. It also flags whether the range is private or public, and handles the two special cases people commonly get wrong: /31, used for point-to-point links with just two addresses, and /32, which identifies exactly one host.
How to use
- Enter an address with a prefix, for example 192.168.1.0/24. Omit the prefix and it is treated as /32.
- Click one of the preset ranges to see common cases quickly.
- Results update as you type.
- Click Copy on whichever value you need.
Frequently asked questions
Why are there two fewer usable hosts than total addresses?
The first address identifies the network itself and the last is the broadcast address; neither can be assigned to a machine. /31 and /32 are exceptions, since later standards allow them to be used differently.
Which ranges are private?
Three, defined in RFC 1918: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. They are for internal networks only and are not routable on the public internet.
What is a wildcard mask for?
It is the bitwise inverse of the subnet mask, used mainly in Cisco access control lists and OSPF configuration.