IP Subnet Calculator
Enter an IPv4 address with CIDR prefix notation (e.g. 192.168.1.0/24) to instantly see the subnet mask, wildcard mask, network address, broadcast address, first and last usable hosts, total addresses, and binary representations. Runs in your browser.
Calculate core IPv4 subnet information from CIDR notation, including mask, wildcard mask, network, broadcast, host range, address counts, class label, and binary forms.
How to calculate an IPv4 subnet
- Enter an IPv4 address followed by a CIDR prefix such as 192.168.1.10/24.
- Press Calculate or Enter.
- Review the subnet mask, network, broadcast, host range, counts, class, and binary values.
How the subnet calculation works
The tool converts IPv4 octets to a 32-bit unsigned integer, creates the prefix mask, then derives network and broadcast values with bitwise operations.
For /31 and /32 it does not subtract network and broadcast addresses from the usable-host count; the class label is only the traditional first-octet A/B/C/D/E classification.
Privacy and limitations
The IPv4 address is calculated locally and is never queried against a network service. This is an IPv4 CIDR arithmetic tool only; it does not support IPv6, routing tables, DNS, geolocation, or live network discovery.
IPv4 Subnet Calculator FAQ
What input format is required?
IPv4 CIDR notation such as 10.0.0.1/8.
Does it support IPv6?
No. This calculator is IPv4-only.
How are /31 and /32 handled?
Their total address count is also used as the usable-host count.
What is the wildcard mask?
It is the bitwise inverse of the subnet mask.
Does the tool look up my IP online?
No. It performs only local arithmetic.