Subnet / CIDR Calculator online — free

Why use this tool?

• Runs locally in browser
• Fast & private
• No sign-up

How it works

1. 1Open the Subnet / CIDR Calculator page — no registration required.
2. 2Paste or type your input into the editor.
3. 3Adjust settings and review the live preview (runs locally in browser).
4. 4Copy the output or download the processed file to your device.

Common use cases

• Format GraphQL or curl commands for documentation
• Generate HMAC, PKCE, or test tokens for OAuth flows
• Parse user agents or network details during debugging
• Prototype requests before moving them to Postman or code

Tips & comparisons

• Compared with desktop apps, this online subnet / cidr calculator starts instantly and needs no updates — bookmark it for repeat tasks.
• Cloud upload services may store copies of your files; this browser tool keeps processing local when the feature allows it.
• For batch or enterprise workflows, combine this tool with Tentaco studios or export results to your own pipeline.

Privacy & data handling

Tentaco runs this tool in your browser whenever possible. Text and structured input you paste are handled in the page session unless the tool explicitly fetches remote data. Close the tab or clear the page after use on shared computers. Features that call external APIs (such as URL fetchers) only send the data required for that request.