CIDR / Subnet Calculator
Processing: API. Processed by cent-ai's API: sent to our server, held in memory, never stored.Enter IPv4 CIDR notation to get the network address, broadcast address, netmask, and usable host range. Nothing you enter here is stored or logged.
How to use it
- Enter an IPv4 address with a prefix length, e.g.
10.0.0.0/24. - The network details appear automatically, or select “Calculate” to run it immediately.
- Copy the result to your clipboard.
Example
Select “Use example” above to load a sample network, or try input like:
192.168.1.0/26
Privacy and security
- Input is sent to our API only to compute the network details; it is never persisted or logged.
- Requests are not included in analytics or error reporting.
- Request bodies are limited in size to keep the service responsive for everyone.
Limitations
- IPv4 only — IPv6 CIDR notation is rejected today.
- Octets with leading zeros (e.g.
10.0.0.01) are rejected rather than guessed at.
FAQ
Does this support IPv6?
Not yet — only IPv4 CIDR notation is supported today.
What happens if I enter a host address instead of a network address?
It's normalized down to the network address for that prefix — e.g. 192.168.1.130/26 is treated the same as 192.168.1.128/26.
Why does a /31 or /32 show no broadcast address?
A /32 is a single host route with no network/broadcast concept. A /31 is a point-to-point link (RFC 3021) where both addresses are usable and neither is reserved.