Inspect the network
See the normalized CIDR, network, broadcast, masks, full and usable ranges, address counts, and offline classification details.
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IP/CIDR CALCULATOR
Understand an IPv4 network before you use it.
Enter an IPv4 address or CIDR, inspect the exact network facts, compare route lists, and split a subnet into smaller networks on your Mac.
Download for Mac
Free download. Requires macOS 14 or later.
WHAT IT HELPS WITH
Move from one address to a workable network plan.
Check the plan
Test whether an address belongs to the source network and compare target routes for containment, adjacency, or overlap.
Split or aggregate
Divide a source network into uniform child subnets or reduce a route list into the smallest exact CIDR set.
BOUNDED PLANNING
Review useful route sets without losing the source.
Compare and Aggregate each accept through 64 KiB of text and 500 physical lines. Valid rows remain visible alongside line-specific errors.
Subnet splitting reports the full child count and shows at most 256 rows at once.
500 linesCompare and Aggregate input
64 KiBText limit for each route-list workflow
256 rowsMaximum visible split result
INCLUDED IN FREE
The complete IPv4 planning workflow.
Subnet facts, address policies, containment, Compare, Aggregate, Split, inspector details, JSON, and copy actions are included in Free.
OFFLINE REFERENCE
Classification without a lookup.
Address classification uses a bundled IPv4 reference inside the app. Entered addresses, route lists, and calculated output remain in the current workbench session.
LOCAL BY DEFAULT
Your network plan stays on your Mac.
Parsing, calculations, comparisons, aggregation, and subnet splitting run locally. The workbench makes no network or DNS request.
Read the Dev Workbench privacy policy