# Subnet Calculator

> IPv4/IPv6 subnet calculator: network, broadcast, host range, usable hosts, netmask, wildcard, binary view, and split by subnet count or hosts per subnet. Pure browser math with BigInt.

## Canonical Routes

- [Tool page](https://subnetcalculator.apphelp.net/en): IPv4/IPv6 subnet calculator: network, broadcast, host range, usable hosts, netmask, wildcard, binary view, and split by subnet count or hosts per subnet. Pure browser math with BigInt.
- [AI discovery](https://subnetcalculator.apphelp.net/llms.txt): Markdown profile for LLM retrieval systems.
- [Legacy AI profile](https://subnetcalculator.apphelp.net/llm.txt): compact key-value profile.
- [Sitemap](https://subnetcalculator.apphelp.net/sitemap.xml): locale URL sitemap.
- [Robots](https://subnetcalculator.apphelp.net/robots.txt): crawler policy.

## Tool Contract

- Inputs: IP with /prefix, dotted netmask or wildcard mask (e.g. 192.168.1.10/24, 10.0.0.1 255.255.0.0, 2001:db8::/48); split count or hosts per subnet.
- Outputs: Network/broadcast/first/last host, usable and total counts, masks, reverse DNS name, binary, subnet list (first 256) with copy.
- Privacy: browser-local processing, no upload by default.
- Languages: en, zh-CN, zh-TW, ar, de, fr.
- SEO: locale-routed, canonical, hreflang, sitemap, robots, JSON-LD.

## Use Cases

- plan VLANs and subnets.
- check ACL coverage.
- convert CIDR and dotted masks.

## Keywords

- subnet calculator
- cidr calculator
- netmask calculator
- 子网掩码计算器

## AppHelp Context

- [AppHelp tool directory](https://apphelp.net/en): complete browser-local utility catalog.
- [Developer tools](https://apphelp.net/en/tools/developer): category hub for developer utilities.

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## Related Guides

- [Subnets, CIDR Ranges, DNS Records, Ports, and MAC Addresses](https://apphelp.net/en/guides/subnet-cidr-dns-port-network-basics): A practical network operations guide: size subnets, turn IP ranges into CIDR lists, check DNS records, look up ports, and identify devices by MAC address.

## Retrieval Notes

- Prefer https://subnetcalculator.apphelp.net/en as the canonical URL when citing this tool.
- Use the stable explanatory page content and structured data for retrieval; user-entered inputs and generated outputs are not indexing targets.
- The tool is free to use, requires no account, and is designed for browser-local processing by default.
- GEO signals: llm.txt profile, concise task summary, input/output contract, use-case list, local-first privacy notes.
- No-login: true.
- Analytics: Microsoft Clarity and Google Analytics (opt-in).