IP Subnet Calculator
Calculate network address, broadcast, and host range from an IP address and CIDR prefix.
IP Address / CIDR
Related Tools
Subnetting Basics: CIDR, Masks, and Host Ranges
Subnetting divides an IP network into smaller networks. Whether you are configuring a home router, designing VPC subnets in the cloud, or writing firewall rules, the same arithmetic applies.
1. Reading CIDR Notation
192.168.1.10/24 means: the address is 192.168.1.10, and the first 24 bits (192.168.1) identify the network. The remaining 8 bits give 2⁸ = 256 addresses, from .0 (network) to .255 (broadcast).
2. Quick Reference
- /30 — 4 addresses, 2 usable (small point-to-point links)
- /24 — 256 addresses, 254 usable (typical LAN)
- /16 — 65,536 addresses (large private network)
- /8 — 16.7M addresses (the whole 10.x.x.x private range)
3. Cloud Networking Tip
Cloud providers reserve extra addresses per subnet (AWS reserves 5, for example), so a /28 in a VPC yields 11 usable addresses, not 14. Always check your provider's documentation when sizing subnets.