/24 — common LAN
256 IPv4 addresses, normally 254 usable hosts. The last 8 bits are host bits.
TechFinity toolkit
CIDR / Subnet Calculator
Explore IPv4 and IPv6 networks visually: masks, ranges, binary boundaries, subnet splits, reverse DNS, containment, and address planning.
Address planning
Enter a network or host address
A host address such as 192.168.10.37/24 is fine; the calculator derives the network automatically.
Normalized network—
Prefix—
Total addresses—
Scope—
Network details
Canonical boundaries and masks.
Address details
Representation and useful derived values.
Bit boundary
Network bits are highlighted; host bits are muted.
Contains address?
Check whether another address belongs to this CIDR.
Enter an address to test.
Adjacent networks
Move by one network of the current prefix size.
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Split this IPv4 network
Choose a longer prefix to see the child subnets. Large results are capped on screen.
| # | Subnet | First usable | Last usable | Broadcast | Usable |
|---|
Learn by example
The calculator is also a subnetting reference—use these as starting points and change the prefix.
/30 and /31 — point-to-point
/30 provides two traditional usable hosts. RFC 3021 /31 links use both addresses with no broadcast role.
IPv6 /64
A standard IPv6 LAN prefix leaves 64 interface-ID bits and contains 264 addresses.
Wildcard masks
The wildcard is the inverse of the IPv4 subnet mask. It is frequently used in ACL and routing configuration.
Network vs. host bits
The prefix length tells you how many leading bits identify the network. Everything after the boundary identifies addresses inside it.
Private IPv4 space
RFC1918 ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.