BetaLocal processinghigh sensitivity

IPv4/IPv6 CIDR & VLSM Calculator

Calculate exact IPv4 and IPv6 network boundaries locally with arbitrary precision

This tool is beta

Do not rely on this result for security, compliance or production changes until the tool passes independent verification.

Workbench

Use IPv4/IPv6 CIDR & VLSM Calculator

Inputs are not saved by the workspace.

Beta: exact integer arithmetic runs locally. IPv4 /31 follows RFC 3021 point-to-point semantics; IPv6 has no broadcast address.

IPv4 or IPv6 CIDR

Enter required usable hosts. Requests are allocated largest-first within the parent CIDR.

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Beta: requires independent specialist review before promotion to Verified.
IPv4 VLSM uses conventional network/broadcast reservation and allocates largest requests first.
IPv6 zone identifiers are ignored and IPv6 VLSM planning is not included.
Input is processed locally and retained only in this browser tab.

These links carry no input or output. Cross-tool payload handoff is kept in memory only when a compatible tool explicitly offers it.