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CIDR Exclusion Calculator

Subtract IPv4 exceptions from network lists and export the exact remaining CIDRs. Work locally without uploading network information.

Runs entirely on your deviceNo uploads, accounts, cookies, or personal tracking.

Subtract excluded ranges

Local processing · no input storage

Network tools
CIDRs, single addresses, or start-end ranges; one per line.
Ranges outside the included space have no effect.

The result includes every remaining address, including network and broadcast addresses. Output is limited to 5,000 CIDRs.

Text lists: up to 500 non-empty lines and 256 KiB per field. Tabular results: up to 5,000 rows.

Enter your data, then select subtract excluded ranges.
1. Add your data

Enter your network data or load the worked example.

2. Choose the result

Subtract excluded ranges and review the result and assumptions.

3. Save it locally

Copy the result or download it for your engineering workflow.

About this tool

Use CIDR Exclusion Calculator without an upload

Subtract IPv4 exceptions from network lists and export the exact remaining CIDRs. Work locally without uploading network information.

The operation runs in the current browser tab. Tool input is not included in aggregate analytics, and the standalone download makes no analytics requests.

Network toolsDeveloper tools