💻 CIDR Subnet Calculator — IPv4 Network, Hosts and Mask
Enter an IPv4 address and a prefix length from 0 to 32. The calculator shows the network, broadcast, usable range, subnet mask, wildcard mask, and host count.
How it works
- Enter any IPv4 address and the CIDR prefix length from 0 to 32.
- Press Calculate subnet to mask the address and derive the network and broadcast.
- Read the usable host range, subnet mask, wildcard mask, and total host count.
Examples
- 192.168.1.25/24 is network 192.168.1.0, broadcast 192.168.1.255, mask 255.255.255.0.
- 10.0.0.15/30 is network 10.0.0.12, broadcast 10.0.0.15, usable hosts 10.0.0.13 and 10.0.0.14.
- A /32 is a single host address with no separate network and broadcast split.
Frequently asked questions
Which IP version does this support?
IPv4 only. Each octet must be an integer from 0 to 255, and the prefix must be an integer from 0 to 32.
Why can the usable host count be zero?
For /31 and /32 there is no traditional network-plus-broadcast pair with spare hosts. /31 is often used as a point-to-point link, and /32 is a single address.
Is the address looked up online?
No. The mask math runs in your browser. The tool does not check who owns the address.
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