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IPv4 Subnet Calculator

Enter an IPv4 CIDR to get a complete subnet report.

Local execution receiptinput path disclosedTool content stays out of MonoTools URLs and API requests.
Working input
Browser memory
Cross-tool handoff
Session only · 10 min
URL payload
Never
Export
Explicit action

Verify it: open DevTools Network, clear the log, use the tool, then inspect fetch/XHR requests. Page assets and optional aggregate analytics may use the network; tool input is not included.

Full privacy model
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How to use

  1. 01Enter an IPv4 CIDR such as 192.168.10.42/24.
  2. 02Review network, broadcast, netmask and RFC 3021 host semantics.
  3. 03Split the network, compare inclusion or compute a covering supernet, then export child ranges as CSV.
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FAQ

Does it support IPv6?
Not in this tool. It focuses on fast IPv4 CIDR math. IPv6 planning deserves a separate interface.
How are /31 and /32 handled?
A /31 exposes both addresses as point-to-point endpoints per RFC 3021. A /32 represents one host route.
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