What is an IP broadcast address?
An IP broadcast address is the last address in an IPv4 subnet. It is used to send a packet to all hosts on that subnet at once. If your network is 192.168.1.0/24, the broadcast address is 192.168.1.255. Network devices use this address for discovery, announcements, and certain legacy protocols.
Knowing the broadcast address is useful when designing VLANs, troubleshooting DHCP behavior, validating firewall rules, and making sure hosts are placed in the right subnet.
How to use this calculator
Accepted input formats
- IP + CIDR in one field: 10.0.5.23/22
- IP and prefix separately: IP = 10.0.5.23, Mask = 22
- IP and dotted mask: IP = 10.0.5.23, Mask = 255.255.252.0
What you get back
- Network address
- Broadcast address
- Usable host range
- Total and usable host counts
- CIDR prefix, subnet mask, wildcard mask, and binary values
Quick explanation of the math
IPv4 addresses are 32-bit numbers. A subnet mask tells us which bits represent the network portion and which represent host bits.
- Network address = IP AND Subnet Mask
- Broadcast address = Network address with all host bits set to 1
Example: for 192.168.10.44/26, the subnet has 64 total addresses. The network is 192.168.10.0 and the broadcast address is 192.168.10.63.
CIDR reference (common sizes)
- /24 → 255.255.255.0 → 256 total addresses
- /25 → 255.255.255.128 → 128 total addresses
- /26 → 255.255.255.192 → 64 total addresses
- /27 → 255.255.255.224 → 32 total addresses
- /28 → 255.255.255.240 → 16 total addresses
- /29 → 255.255.255.248 → 8 total addresses
- /30 → 255.255.255.252 → 4 total addresses
Common subnetting mistakes
- Using a non-contiguous subnet mask (invalid mask patterns).
- Forgetting that /31 and /32 are special cases.
- Assigning network or broadcast addresses to normal host devices in standard subnets.
- Mixing up wildcard masks with subnet masks in ACL configurations.
FAQ
Can I use this for IPv6?
No. This calculator is intentionally designed for IPv4 broadcast calculations.
What happens with /31 and /32?
/31 is typically used for point-to-point links and includes two usable endpoints. /32 describes a single-host route, so network and broadcast resolve to the same address.
Why is broadcast still relevant?
Even in modern routed networks, broadcast boundaries matter for ARP, local discovery, and reducing unnecessary traffic in large Layer 2 domains.