KoguNavi

CIDR / Subnet Calculator

Enter an IPv4 address with a prefix, or paste a CIDR block, to inspect subnet ranges, start/end usable IPs, private-range status, overlap, and simple split suggestions.

Developer tools

What it helps with

  • Check usable IP counts before choosing a subnet
  • Find the start and end usable IPs for an address and prefix
  • See whether a CIDR block is private
  • Check simple overlap against existing VPC ranges

How to use

  1. Enter an IPv4 address with a prefix such as 121.6.100.188 and /30, or paste a CIDR block such as 10.0.0.0/24.
  2. Optionally add required host count or existing CIDRs for overlap checks.
  3. Review start/end usable IPs, address ranges, usable IP count, netmask, and simple split suggestions.

Examples

Private /24

Input

10.0.1.0/24

Output

10.0.1.0 - 10.0.1.255, 254 usable

Public /30

Input

121.6.100.188/30

Output

121.6.100.189 - 121.6.100.190 usable

Small subnet

Input

192.168.10.64/27

Output

30 usable addresses

Good to know

  • IPv4 only in this version.
  • 3-zone split suggestions are simple math, not cloud-provider architecture advice.
  • Does not inspect real VPCs or route tables.
  • No external network or cloud API calls are made.

FAQ

Does this support IPv6?
No. This version focuses on IPv4 CIDR blocks.
Does it inspect my real cloud network?
No. It only calculates values from the CIDRs you enter and does not call cloud APIs.
Are split suggestions architecture advice?
No. They are simple CIDR math to help planning; review cloud-provider and team conventions before use.

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