CIDR Subnet Calculator
Get network/broadcast address, mask, and host range
Conversion Result
————————IP Membership Check
What is CIDR?
CIDR (Classless Inter-Domain Routing) represents a network as an IP address with a prefix length, e.g. 192.168.1.0/24 means the first 24 bits are the network portion. Compared to the traditional A/B/C classes, CIDR allows much more flexible subnetting and underpins modern networking and cloud platforms.
Key Concepts
- Network Address/The address with all host bits set to 0, representing the network itself
- Broadcast Address/The address with all host bits set to 1, used to send data to all hosts in the segment
- Subnet Mask/Corresponds one-to-one with the prefix length, separating network bits from host bits
- Usable Hosts/Addresses assignable to hosts, typically excluding the network and broadcast addresses
FAQ
What does /24 mean?
It means the first 24 bits are the network prefix, corresponding to subnet mask 255.255.255.0 with 256 addresses in total.
Why don't /31 and /32 subtract 2 usable addresses?
/31 is used for point-to-point links (RFC 3021) where both addresses are usable, and /32 denotes a single host address, so neither subtracts the network and broadcast addresses.
Something broken or missing?
Send feedback