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IPv4 subnet calculator

Processed in this browser

Text limit: 2000000 characters

This tool never uploads your input.

10.0.0.0/22 for a homelab or a ticket. We do arithmetic. We do not discover your WAN address.

A ticket: “give the app team a /27 in 10.4.0.0/16.” This page splits IPv4 CIDR. It is not Shodan and not whatismyip.

User-Agent strings are UA parser. HTTP codes are status reference.

Lab math, not a router push

/24 host counts and broadcast addresses for a homework or a design review. We do not push routes, run IPv6, or query WHOIS. /31 and /32 readings follow the implementation — check the RFC your team actually uses before you renumber production.

How to use it

  1. Enter address and prefix (or mask).
  2. Read network, broadcast, and range.
  3. Double-check overlapping plans in your IPAM — we do not.

Honest limits

Not IPv6. Not a DHCP server. Not permission to scan a network you do not own.

FAQ

IPv6?

Not this page. v6 math is a different tool.

Do you look up my public IP?

No. There is no STUN/WebRTC leak feature here.

Usable hosts on /31 or /32?

Point-to-point and host routes have special cases. Read the result labels; do not assume ‘minus 2’ forever.

ACL wildcard masks?

If the form shows them, treat them as Cisco-style inverses — still just math.

Is the address uploaded?

No.

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