Subnet calculator: IPv4 and IPv6, instantly
Enter a CIDR or an address and mask to get network address, broadcast address, usable host range and host count, for IPv4 and IPv6, calculated entirely in your browser as you type with nothing sent to a server at any point.
- Network address
- 192.168.1.0
- Broadcast address
- 192.168.1.255
- Subnet mask
- 255.255.255.0 (/24)
- Wildcard mask
- 0.0.0.255
- Usable host range
- 192.168.1.1 – 192.168.1.254
- Usable hosts
- 254 (of 256 total addresses)
What the result means
The usable host range excludes the network and broadcast addresses for ordinary IPv4 subnets; /31 and /32 are exceptions with their own usable ranges, as shown above.
Next step
Check your own public IP, or look up DNS records for a domain in this range.
How it works and limits
Enter an address with a prefix (192.168.1.0/24) or a dotted mask (10.0.0.0/255.255.0.0) for IPv4, or an address
with a prefix for IPv6 (2001:db8::/64). The result updates as you type — every calculation happens with plain
arithmetic in your browser’s JavaScript engine, nothing is sent to a server.
Reading the result
For IPv4: the network and broadcast addresses bound the subnet, the usable host range excludes both (except for /31 point-to-point links, RFC 3021, where both addresses are usable, and /32, a single host). For IPv6: there is no broadcast address — every subnet is normally sized at /64 for address autoconfiguration (SLAAC), so a /64 has 264 addresses regardless of how many devices actually use it.
Limits
- This is address-plan arithmetic, not a live reachability check — it does not tell you whether any address in the range is actually in use.
- IPv6 addresses are shown in their RFC 5952 canonical compressed form.
Frequently asked questions
Does this tool send my input anywhere?
No — the math runs entirely in your browser.
Why is the IPv6 host count so large?
A typical IPv6 /64 allocation has 2^64 addresses — far more than any subnet needs; it is sized for address autoconfiguration, not scarcity.