1. 01Enter 192.168.1.10/24, or enter the IP and 255.255.255.0 or 24 separately.
2. 02Read the network, broadcast, usable hosts, total addresses and the binary view.
3. 03Use the CIDR and netmask table to switch quickly between /8 and /32.
4. 04In the subnet splitter, compute the new prefix and the list by subnet count or hosts per subnet.

• IPv4 only; IPv6, DNS names and host names are not handled.
• The CIDR prefix must be an integer from 0 to 32; a dotted mask must be a legal mask of contiguous ones followed by contiguous zeros.
• /31 is computed as a point-to-point network with two usable addresses per RFC 3021; /32 is a single-host route with no traditional broadcast address.
• Splitting by host count reserves network and broadcast addresses for ordinary subnets and keeps at least 2 host bits; that suits traditional IPv4 planning and is not the allocation policy of every special-purpose network.
• The subnet list actually prints at most the first 128 rows; when there are theoretically more, the page shows the total and notes the truncation.
• “Public or special address” and the traditional class A/B/C labels come from local rules; RPKI, ASN, WHOIS and live routing tables are not queried.

The IP and CIDR are handled with bit operations locally in the browser; no request is sent to those addresses or to any lookup service.