Broadcast Address Calculator
Find the broadcast address of a network from its IP address and subnet mask.
About Broadcast Address Calculator
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
Worked example
With the default values below, Broadcast Address Calculator returns Broadcast Address of 172.16.7.255. Change any input above and every figure here is recalculated in your browser.
Inputs used
- IP Address
- 172.16.5.130
- Prefix Lengthaccepts 0–32
- 22
Results
- Broadcast Address
- 172.16.7.255
- Network Address
- 172.16.4.0
- Subnet Mask
- 255.255.252.0
Step by step
- 1Compute subnet mask= 255.255.252.0
- 2Compute network address= 172.16.4.0
- 3Compute broadcast address= 172.16.7.255
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
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.