Text and developer tools
IPv4 CIDR and subnet calculator
Calculate an IPv4 network, subnet mask, wildcard, address range and host count with explicit /31 and /32 handling.
Runs in your browser. Inputs stay on this page and are not uploaded or added to the URL.
Your result
How to use this tool
Enter any IPv4 address with its prefix length. The calculator derives the containing network and final address, subnet and wildcard masks, and the conventional host range. It uses address arithmetic only and sends no network probes.
For prefixes /0–/30, the conventional host count excludes network and broadcast addresses. A /31 is interpreted as an RFC 3021 point-to-point link with two usable addresses; /32 denotes one host. Special-purpose address allocations, device support and your network’s policy can further constrain actual use.
Worked example
192.168.1.42/24 belongs to 192.168.1.0/24. Its mask is 255.255.255.0 and its conventional host range is 192.168.1.1–192.168.1.254.
References and method
Contifield is an independent utility site. Reference publishers do not endorse this tool.
Related tools
Punycode and IDN domain converter
Convert an internationalized domain between Unicode and ASCII Punycode with browser URL processing and round-trip validation.
Unicode code point inspector
Inspect Unicode code points, UTF-16 units, UTF-8 bytes and all four normalization forms: NFC, NFD, NFKC and NFKD.
IPv4 and IPv6 CIDR overlap checker
Compare two IPv4 or IPv6 network prefixes for overlap, containment, equality or adjacency with exact address ranges and counts.