IP Addressing and Subnetting
Calculated locally
CIDR to Subnet Mask Converter
Convert IPv4 CIDR prefixes into subnet masks, wildcard masks, binary masks, and host capacity details.
Learn before you deploy
Reference PacketToolbox learning content related to this workflow.
Tool input
Use the fields below and run the calculation or generation locally.
Results
Review output and validation notes before production use.
How it works
Enter a CIDR prefix, then calculate to see mask and host details instantly.
All processing runs in-browser with no external API dependency.
Practical example
Example: /27 returns 255.255.255.224, wildcard 0.0.0.31, and 30 usable hosts.
Related tools
Use these together for complete design and troubleshooting workflows.
- IPv4 Subnet Calculator for subnet boundary and wildcard checks.
- VLSM Planner for hierarchical IPv4 allocation.
- Route Summarization Calculator for clean route advertisement planning.
- Cisco ACL Builder for policy-generation workflows.