Looking for a ip subnet calculator with cidr notation? This free tool gives you network, broadcast, mask and usable host range from IP and CIDR. Just enter your numbers and press Calculate — results are instant.
An IP subnet is defined by an address and a CIDR prefix like /24. The prefix says how many bits of the address are the network part; the rest are host bits. The network address is the IP with the host bits set to zero, the broadcast address has them all set to one, and the usable hosts are everything in between. A /24 has 256 addresses and 254 usable hosts, because the network and broadcast addresses themselves cannot be assigned to a device.
Example: IP address 192.168.1.10 · CIDR prefix /24
Usable Hosts: 254
It means the first 24 bits of the 32-bit address are the network part and the remaining 8 bits are for hosts. A /24 has 256 addresses; a /25 has 128, and a /16 has 65,536.
Two addresses are reserved: the network address (all host bits zero) and the broadcast address (all host bits one). Neither can be given to a device.
Yes. Addresses starting 192.168, 10, or 172.16–172.31 are private — used inside homes and offices, not on the public internet. Your router gives your devices addresses from these ranges.
They are special cases with no usable hosts in the usual counting: /32 is a single address, and /31 is used for point-to-point links. The calculator shows 0 usable hosts for both.