Subnet Calculator & IP Planner

Subnet Calculator does IPv4 subnet math without the noise. Enter an address and a prefix, get everything you need instantly.

WHAT YOU GET

- Network and broadcast addresses
- Usable host range, first and last host
- Netmask and wildcard mask
- Total and usable host counts
- Binary breakdown of the address
- Address type detection: RFC1918 private, public, loopback, APIPA
- Calculate by CIDR prefix or by required host count

CIDR REFERENCE TABLE

Every prefix from /0 to /32 with its netmask, host count, and how many subnets fit inside a parent block. Switch the parent between /8, /16, and /24 to see the numbers that matter for your design.

HISTORY

Every calculation is saved automatically. Tap any entry to load it back. Swipe to delete, or clear the whole list at once.

BUILT FOR ENGINEERS

Written by a network engineer for the people who actually work in the routing table. Dark interface for NOC screens and late-night maintenance windows. Monospaced output so addresses line up when you compare them.

PRIVACY

Everything runs on your device. No account, no sign-in, no servers. No advertising, no analytics, no crash reporting, no tracking of any kind. Your calculation history stays on your phone and is never transmitted anywhere.

Free, with no ads.