IP Subnet Calculator
Calculate IPv4 subnet details locally from either CIDR notation or an address paired with a subnet mask.
How to use it
- Choose CIDR notation or separate address and subnet-mask input
- Enter a strict IPv4 value such as 192.168.1.10/24
- Calculate and review the network, broadcast, usable range, counts, and masks
- Copy the results or clear all inputs before another calculation
The calculator validates every octet, prefix length, and contiguous mask before producing a result. It shows the network address, broadcast address, first and last usable hosts, total address count, usable host count, wildcard mask, CIDR prefix, and subnet mask. Point-to-point /31 networks and single-host /32 routes are handled explicitly instead of applying the usual two-address deduction. The private classification refers only to the RFC1918 ranges; other values are described as public or non-private. All arithmetic stays in your browser. The tool does not contact the address, inspect a network, determine ownership, or claim that any host is reachable.
FAQ
/31 exposes both point-to-point endpoints as usable, while /32 represents one address and one usable host.
No. It performs arithmetic only and makes no reachability or ownership claim.
No. Validation and calculation stay in your browser.