Free browser tool
IPv4 Subnet Calculator
Calculate network, netmask, broadcast address and usable range from IPv4 CIDR notation.
When to use the IPv4 Subnet Calculator
Use it when planning networks, VPCs or firewall rules and you need the network, broadcast address and usable host range of a CIDR block.
Examples
- 10.0.1.0/24 gives 254 usable hosts from 10.0.1.1 to 10.0.1.254.
- Split a /16 VPC into /20 subnets for each availability zone.
Common mistakes
- Forgetting that cloud providers reserve extra addresses in each subnet.
- Overlapping CIDR ranges between VPCs that later need peering.
Created by Muhammad Irfan Aslam, Senior Systems & Cloud Engineer.
Case study: AWS infrastructure architecture →Tutorial on LearnWithIrfan: Subnetting for Linux administrators →