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
This calculator computes the network address, broadcast address, subnet mask, and usable host range for any IPv4 address and CIDR prefix.
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 (no IPv6 support in this calculator).
- /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 the difference between the network address and the first usable host?
The network address (e.g. 192.168.1.0) identifies the subnet itself and cannot be assigned to a device. The first usable host is one address above it.
Why does a /31 subnet not have a separate broadcast address?
RFC 3021 defines /31 subnets specifically for point-to-point links, allowing both addresses in the 2-address block to be used as hosts, since a broadcast address isn't needed on a link with only two endpoints.
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.