NetworkRuns locally · No upload

CIDR Calculator

Parse CIDR notation to get network address, broadcast address, subnet mask, and usable host range. Essential for network planning and DevOps.

Private by design

Everything runs in your browser. Your input is never uploaded, stored, or logged on our servers.

Works offline after load

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CIDR Calculator & Subnet Mask Online (Free)

Calculate subnet ranges, network addresses, and host counts from CIDR notation. Free, browser-based networking tool.

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Frequently asked questions

Is this tool free?+

Yes. Every Utiliio utility is free with no sign-up, usage limits, or paywalls.

Do you store my data?+

No. Processing happens entirely in your browser. Your input never leaves your device.

Can I use this tool offline?+

Yes. Once the page loads, most tools continue working without an internet connection.