AtlasCalc💻 TechnologybeginnerOffline
IP Subnet Calculator
IPv4 subnet breakdown from CIDR (e.g. 192.168.1.0/24).
Inputs
Enter your values below.
Result
Your answer appears here.
Enter values and press Calculate — the result appears here.
How it works
The formula behind this calculator.
hosts = 2^(32 − CIDR) − 2; network = IP AND mask
- IP
- 32-bit IPv4 address
- CIDR
- Network prefix length, 0–32
The CIDR suffix tells you how many bits are the network portion. The remaining bits are for hosts. The all-zeros and all-ones host addresses are reserved.
Example: 192.168.1.0/24 → 256 addresses, 254 usable hosts
Ref: RFC 4632 (Classless Inter-Domain Routing)
Tips
- 💡 The subnet mask determines network size. /24 = 256 addresses, /16 = 65,536.
- 💡 Private ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. They aren't routable on the public internet.