IPv4 Subnet Calculator
Enter an IP and CIDR prefix to get the network, broadcast, mask, wildcard, host range and usable host count — the complete subnet breakdown, instantly.
About IPv4 Subnet Calculator
IPv4 Subnet Calculator gives you the complete breakdown of any subnet from an IP and CIDR prefix — network and broadcast address, subnet mask, wildcard mask, first and last usable host and total host count — recalculated instantly as you type.
How to use IPv4 Subnet Calculator
- 1Paste or type your input into the box above — a sample is pre-filled so you can try it instantly.
- 2Set any options on offer (mode, key, format) to match what you need.
- 3The result appears the moment you type — no button to press, no waiting.
- 4Click Copy to grab the output — IPv4 Subnet Calculator keeps everything on your device.
Why use IPv4 Subnet Calculator?
- ✓Planning VLANs and address ranges for an office, lab or cloud VPC
- ✓Answering 'is this IP in that subnet?' during firewall and routing work
- ✓Studying for CCNA/Network+ — every intermediate value is shown, not just the answer
- ✓100% free with no sign-up, no watermark and no usage limits
- ✓Runs entirely in your browser — your text and keys are never uploaded, stored or logged
- ✓Works offline once loaded, with instant results and one-click copy
Frequently asked questions
How many usable hosts are in a /24, /26 or /30?+
A /24 has 254 usable hosts (256 minus network and broadcast), a /26 has 62, and a /30 has 2. In general it is 2^(32−prefix) − 2, with /31 point-to-point links (2 usable, RFC 3021) and /32 single hosts as special cases — the calculator handles both.
What is the wildcard mask used for?+
It is the bitwise inverse of the subnet mask — 0.0.0.63 for a /26. Cisco ACLs and OSPF network statements match on wildcard masks rather than subnet masks, which is why the calculator shows it alongside.
Is it free to use?+
Yes — completely free with no sign-up, no account and no usage limits. There is no paywall, so you can encode, decode and convert as much as you like.
Is my data private and secure?+
Yes. This tool runs entirely in your browser using client-side JavaScript — your input is never uploaded to a server, stored or logged. Once the page has loaded you can use it offline, which makes it safe for tokens, keys and confidential data.
Related Developer tools
JSON to TypeScript Interface Generator
Paste JSON and get clean TypeScript interfaces instantly — nested objects become named interfaces, arrays of objects are merged with optional properties detected, unions inferred. 100% client-side.
● LiveCIDR to Subnet Mask Converter
Convert a CIDR prefix (/0–/32) to its dotted-decimal subnet mask and wildcard mask, and back again — with host counts for each prefix length.
● LiveVLSM Subnet Planner
Plan variable-length subnets: enter a base network and the hosts each subnet needs, and get an optimal, non-overlapping allocation — largest-first, no wasted space.
● Live