IP Range Calculator
Calculate the usable IP address range for a subnet, given an IP address and CIDR prefix.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter an IP address and CIDR prefix to calculate the usable IP address range for that subnet.
Your result
172.16.0.1
First usable IP
Last usable IP172.16.0.62
Usable host count62
Network address172.16.0.0
Broadcast address172.16.0.63
AI explanation
Formula
Usable range = network address + 1 to broadcast address − 1 (all addresses for /31, single address for /32)Worked example
172.16.0.1 / 26
| Field | Value |
|---|---|
| IP address | 172.16.0.1 |
| CIDR prefix (/n) | 26 |
| First usable IP | 172.16.0.1 |
| Last usable IP | 172.16.0.62 |
| Usable host count | 62 |
| Network address | 172.16.0.0 |
| Broadcast address | 172.16.0.63 |
Assumptions
- IPv4 only.
- /31 networks follow RFC 3021 (both addresses usable); /32 is a single host route.
Frequently asked questions
What is a usable IP range?
The set of addresses within a subnet that can actually be assigned to devices — it excludes the network address (identifying the subnet itself) and the broadcast address (used to reach every device on the subnet at once).
How do I find the range for a specific subnet size?
Enter any IP address within the subnet along with the CIDR prefix that defines its size — the calculator finds the containing subnet and its usable range automatically.
Does the range change if I use a different IP within the same subnet?
No — any IP address within the same subnet (same network address for that prefix length) produces the same range.