Networking
IP & CIDR Calculator
Calculate IPv4 network ranges, host capacity, membership, and bounded subnet previews from an address and prefix.
Enter an IPv4 address and prefix, such as 192.168.1.0/24.
Enter another IPv4 address to check whether it falls inside the network above.
Subnet split preview
The child prefix must be at least the parent prefix; at most 64 subnets are shown.
How to use this IP / CIDR calculator
Enter an IPv4 address and prefix to see the network address, broadcast address, masks, address count, and traditional usable host range. You can also check another IP and preview child subnets. All calculations run in your browser.
Masks and address ranges
The subnet mask identifies the network portion; the wildcard mask is its bitwise complement. /0 covers the whole IPv4 address space, while /32 covers one address. Traditional usable hosts exclude the network and broadcast addresses.
Frequently asked questions
Why does /31 have no traditional host range?
Traditional rules treat the two addresses as the network and broadcast addresses, leaving zero usable hosts. RFC 3021 defines a point-to-point exception in which both /31 addresses can be used as endpoints.
How many addresses are in /0?
A /0 prefix has zero network bits and covers 2^32 addresses: 4,294,967,296 total and 4,294,967,294 traditional usable hosts.
Is my input uploaded?
No. Parsing, calculations, membership checks, and subnet previews happen locally in your browser.