Broadcast Address Calculator
Find the broadcast address of a network from its IP address and subnet mask.
Inputs
Broadcast Address
172.16.7.255
Network Address
172.16.4.0
Subnet Mask
255.255.252.0
Step by step
Compute subnet mask
/22
= 255.255.252.0
Compute network address
172.16.5.130 AND 255.255.252.0
= 172.16.4.0
Compute broadcast address
172.16.4.0 OR NOT(255.255.252.0)
= 172.16.7.255
How it works
The broadcast address is the last address in a subnet — all host bits set to 1. It is calculated by ORing the network address with the inverse (bitwise NOT) of the subnet mask. Packets sent to this address are delivered to all hosts on the subnet.
Formula
Broadcast address
broadcast = network_address OR NOT(subnet_mask)
- N
- Network address
- M
- Subnet mask
Frequently Asked Questions
Can I assign the broadcast address to a host?
No — the broadcast address is reserved for reaching all hosts on the subnet simultaneously. Assigning it to a device would cause network conflicts and unpredictable behavior.
What is the broadcast address of a /31 subnet?
RFC 3021 defines /31 subnets for point-to-point links with no broadcast address and no network address — both addresses are usable as host addresses, since broadcast is unnecessary on a two-device link.