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Subnet Calculator

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IPv4 CIDR calculator — network, broadcast, mask, hosts, and wildcard.

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Client-Side
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Network

  • Mask255.255.255.0
  • Network192.168.1.0
  • Broadcast192.168.1.255
  • First host192.168.1.1
  • Last host192.168.1.254
  • Hosts254
  • Wildcard0.0.0.255

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  title="Subnet Calculator">
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How to Use

  1. 1 Enter an IPv4 address
  2. 2 Set the CIDR prefix (0–32)
  3. 3 Read mask, network, broadcast, and host range
  4. 4 Copy values into firewall or VPC config

Features

  • CIDR /0–/32
  • Network + broadcast
  • First/last host + count
  • Wildcard mask
  • Client-side

Why it Matters

VPC and firewall tickets always need what is the network for this /27 — this answers without a CLI.

★★★★★

Paste an IPv4 address and CIDR prefix to get network details for firewalls, VPCs, and lab networks.

Frequently Asked Questions

IPv6?
Not in this tool — IPv4 CIDR only.
/31 and /32?
Host counts follow common conventions (/32 = 1, /31 treated as 0 usable hosts).
Private only?
Works for any IPv4 address.
📖

Want to understand the math?

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16 Aug 2026

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Web Config Ops — Subnets, Permissions, HTTP Status & CSS Units

Hub for Tools.Town server and web config math: IPv4 CIDR subnetting, chmod permission modes, HTTP status code lookup, and px ↔ rem conversion — free, in-browser.

16 Aug 2026

5 min read

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