IPv4 Subnet Calculator
Calculate the network address, broadcast address, subnet mask, and usable host range for any IPv4 address and CIDR prefix.
- Free to use
- Accurate results
- No registration required
- Works on all devices
Enter an IPv4 address and CIDR prefix to calculate the network address, broadcast address, subnet mask, and usable host range.
e.g. 192.168.1.10
The number after the slash, e.g. /24
Your result
192.168.1.0
Network address
Broadcast address192.168.1.255
Subnet mask255.255.255.0
First usable host192.168.1.1
Last usable host192.168.1.254
Usable host count254
AI explanation
Formula
Network = IP AND Mask; Broadcast = Network OR (NOT Mask); usable range excludes network/broadcast except for /31 and /32Worked example
192.168.1.10 / 24
| Field | Value |
|---|---|
| IPv4 address | 192.168.1.10 |
| CIDR prefix length | 24 |
| Network address | 192.168.1.0 |
| Broadcast address | 192.168.1.255 |
| Subnet mask | 255.255.255.0 |
| First usable host | 192.168.1.1 |
| Last usable host | 192.168.1.254 |
| Usable host count | 254 |
Assumptions
- IPv4 only — see the IPv6 Subnet Calculator for 128-bit addressing.
- /31 networks follow RFC 3021 (2 usable point-to-point addresses, no separate broadcast); /32 is treated as a single host route.
Frequently asked questions
What is CIDR notation?
Classless Inter-Domain Routing notation expresses a subnet mask as a prefix length (e.g. /24) — the number of leading 1-bits in the mask — rather than as a full dotted-decimal mask.
How many usable hosts does a /24 network have?
254 — a /24 has 256 total addresses, minus 1 for the network address and 1 for the broadcast address.
What's the difference between this and the CIDR Calculator?
They compute the same thing — this page emphasizes the IPv4-specific framing, while the CIDR Calculator emphasizes prefix-length arithmetic that also applies conceptually to IPv6.