CIDR / Subnet Calculator
Enter an address with a prefix (192.168.1.10/24), an address with a netmask (10.0.0.0 255.255.0.0) or an IPv6 network (2001:db8::/32).
About the CIDR / Subnet Calculator
The CIDR / Subnet Calculator shows the network address, netmask, wildcard mask, binary netmask, broadcast address, first and last usable host, total addresses and usable hosts for any IPv4 CIDR, and the network, last address and address count for IPv6. Enter 192.168.1.10/24, or an address with a netmask such as 10.0.0.0 255.255.0.0.
How to use the CIDR / Subnet Calculator
- Enter an IP address with a prefix or a netmask.
- Click Calculate.
- Read the network details and copy what you need.
Frequently asked questions
How are /31 and /32 networks handled?
A /31 is treated as a point-to-point link (RFC 3021): both addresses are usable and there is no broadcast. A /32 is a single host.
Does it support IPv6?
Yes. For IPv6 it shows the network address, the last address and the total number of addresses.
Are my data stored when I use the CIDR / Subnet Calculator?
The text you submit is processed in memory to produce the result and is not saved. Like any web server, Code Converter logs basic visit data (page, IP address and browser) but never the content you paste.
Is the CIDR / Subnet Calculator free, and can I call it from a script?
It is free and needs no account or signup. The same tool is available as a REST endpoint at POST /api/cidr-calculator; see the API documentation for the fields and examples.