Enter an IPv4 address and a CIDR prefix (like /24) to instantly calculate the network address, broadcast address, usable host range, subnet mask, wildcard mask, and the number of usable and total addresses.
Ideal for network planning, configuring routers and firewalls, or studying for certifications. The calculation runs entirely in your browser — no data ever leaves your machine.
What does an IP subnet calculator do?
It takes an IPv4 address and a CIDR prefix and works out the network address, broadcast address, usable host range, subnet mask, and how many hosts the subnet can hold.
What is CIDR notation?
CIDR notation writes a network as an IP followed by a slash and prefix length, such as 192.168.1.0/24, where the number is how many bits belong to the network portion.
How many hosts are in a /24 subnet?
A /24 subnet has 256 total addresses and 254 usable host addresses — the network and broadcast addresses are reserved.
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