Subnet & CIDR Calculator — Free & Private

Calculate IP subnet masks, wildcard masks, network and broadcast addresses, and usable host ranges.

Part of HTTP & API Toolkit. Runs 100% in your browser: your files and data never leave your device. No signup, no ads.

More in HTTP & API Toolkit

• HTTP Status Code Reference
• HTTP Security Header Analyzer
• User-Agent Parser
• Webhook Tester
• HTTP Mock Response Generator
• Fake API Response Generator
• GraphQL Query Builder
• OpenAPI & Swagger Validator

Browse all free tools