Broadcast Address Calculator
Find the broadcast address for any IP address and CIDR prefix. Enter something like 192.168.1.0/24 and this tool instantly returns the broadcast address, the network address, the subnet mask and the usable host range — all computed locally in your browser.
What Is a Broadcast Address?
The broadcast address is the last address in a subnet and is used to send a single message to every device on that network at the same time. When a host wants to reach all other hosts on its local segment in one packet, it sends to the broadcast address rather than to each device individually. In IPv4 every subnet has exactly one broadcast address, and it is always the highest address in the network range.
To find it, you combine your IP address with a CIDR (Classless Inter-Domain Routing) prefix written as IP/prefix, such as 192.168.1.0/24. The prefix length after the slash tells you how many of the 32 bits are reserved for the network. The network address is the lowest address in the range (all host bits zero), and the broadcast address is the highest (all host bits set to one). For a /24, the broadcast of the 192.168.1 network is simply 192.168.1.255.
How to Use This Tool
- Enter an IP address followed by a CIDR prefix, for example
192.168.1.0/24or10.0.0.0/16. - Press Calculate (or hit Enter).
- Read the broadcast address in the results table, alongside the network address, subnet mask and usable range.
- Use it when configuring DHCP scopes, firewalls or broadcast-based protocols such as ARP and NetBIOS.
The calculation runs entirely on your device. Your IP address is never transmitted anywhere, so you can safely work with internal and private ranges without any privacy concern.
Broadcast Address Calculator — Frequently Asked Questions
How do I calculate a broadcast address?
Convert the IP address to a 32-bit number and apply the subnet mask (a run of 1s equal to the prefix length, followed by 0s). The network address is IP AND mask. The broadcast address is the network address with all host bits set to 1 — or equivalently, network OR (inverted mask). For 192.168.1.0/24, the mask is 255.255.255.0 and the broadcast is 192.168.1.255.
Can the broadcast address be assigned to a device?
No. The broadcast address is reserved and cannot be assigned to any host, just like the network address cannot. Together they sit at the two opposite ends of every subnet range, and the usable addresses for devices run strictly between them.
What is the broadcast address of a /24, /25 or /30?
For 192.168.1.0/24 the broadcast is 192.168.1.255. For 192.168.1.0/25 it is 192.168.1.127. For a point-to-point 192.168.1.0/30 the broadcast is 192.168.1.3, which leaves exactly two usable host addresses between the network and broadcast endpoints.
Does IPv6 have broadcast addresses?
No. IPv6 replaced the concept of broadcast with multicast. Instead of one address that reaches every host on the link, IPv6 uses the all-nodes multicast group ff02::1. This calculator and the related IPv6 tools on this site handle that difference — see the Subnet Calculator for IPv4 details and the IPv6 Expander for IPv6 addresses.
Is this broadcast address calculator free and private?
Yes. It is completely free and runs in your browser. The calculation is done locally in JavaScript, so the IP address and prefix you enter are never sent to any server, logged, or stored.