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IPv4 Subnet Calculator

Calculate network boundaries, masks, host ranges, and /31 point-to-point addresses. Work locally without uploading network information.

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

Calculate subnet

Local processing · no input storage

Network tools
Host bits are accepted and the normalized network is shown.

/31 counts assume RFC 3021 point-to-point links; /32 represents one address.

Enter your data, then select calculate subnet.

Technical reference: RFC 3021

1. Add your data

Enter your network data or load the worked example.

2. Choose the result

Calculate subnet and review the result and assumptions.

3. Save it locally

Copy the result or download it for your engineering workflow.

About this tool

Use IPv4 Subnet Calculator without an upload

Calculate network boundaries, masks, host ranges, and /31 point-to-point addresses. 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