IPv4 Broadcast IP Calculator
Enter an IPv4 address and subnet mask (or CIDR notation) to calculate the broadcast address, network address, host range, and more.
Supported formats: dotted decimal mask, /CIDR, or plain CIDR number.
What is a broadcast IP address?
A broadcast IP address is the last address in an IPv4 subnet. It is used to send a packet to
all hosts on the same local network segment. For example, in a 192.168.1.0/24 network,
the broadcast IP is 192.168.1.255.
Broadcast addresses are important for network discovery, ARP-related behavior, and certain legacy protocols. They are also a common exam and interview topic in networking because they test your understanding of subnetting, binary boundaries, and CIDR notation.
How this broadcast IP calculator works
The calculator uses your IPv4 address and subnet mask to identify the network boundary. Once that boundary is known, it computes key values:
- Network Address: the first address in the subnet.
- Broadcast Address: the last address in the subnet.
- First/Last Usable Host: typical host range for devices.
- Total Addresses: all addresses in that subnet block.
- Usable Hosts: addresses generally assignable to devices.
- Wildcard Mask: inverse of the subnet mask, often used in ACLs.
Quick binary idea
Subnet masks split an IPv4 address into network bits and host bits. The network bits stay fixed;
host bits vary. The broadcast IP is obtained by setting all host bits to 1.
The network address is obtained by setting all host bits to 0.
How to use the calculator
- Enter a valid IPv4 address (for example,
10.0.5.12). - Enter a subnet mask (for example,
255.255.252.0) or CIDR (for example,/22). - Click Calculate.
- Review the resulting network, broadcast, and host details.
Tip: You can click Use Example to auto-fill sample values and test the calculator instantly.
Worked subnet examples
Example 1: 192.168.1.34/24
A /24 means 24 network bits and 8 host bits. The network is 192.168.1.0,
and the broadcast is 192.168.1.255. Usable hosts are typically 192.168.1.1
through 192.168.1.254.
Example 2: 172.16.10.130/26
A /26 has blocks of 64 addresses in the last octet: 0, 64, 128, 192.
Since 130 falls in the 128-191 range, the network is 172.16.10.128 and
broadcast is 172.16.10.191.
Example 3: /31 and /32 edge cases
/31 and /32 are special. A /31 is often used on point-to-point links,
while a /32 represents a single host route. The calculator handles these ranges and displays useful
host information accordingly.
CIDR to subnet mask cheat sheet
/8→255.0.0.0/16→255.255.0.0/24→255.255.255.0/25→255.255.255.128/26→255.255.255.192/27→255.255.255.224/28→255.255.255.240/29→255.255.255.248/30→255.255.255.252
Common subnetting mistakes to avoid
- Using a non-contiguous subnet mask (invalid in standard IPv4 subnetting).
- Confusing the network address with the default gateway.
- Treating broadcast addresses as usable host IPs in traditional subnets.
- Mixing CIDR and dotted mask values incorrectly.
- Ignoring private vs public address context when planning networks.
Why broadcast calculations matter
Even in modern routed environments, knowing your broadcast boundaries helps with troubleshooting, VLAN design, DHCP behavior, and reducing unnecessary broadcast traffic. Accurate subnet planning improves performance, security segmentation, and operational clarity.
Frequently asked questions
Is broadcast used in IPv6?
No. IPv6 does not use broadcast in the same way IPv4 does. It uses multicast and anycast mechanisms instead.
Can I enter either a mask or CIDR?
Yes. This tool accepts dotted decimal masks like 255.255.255.0, slash notation like /24,
or plain numbers like 24.
How is usable host count calculated?
For most subnets, usable hosts are total addresses minus network and broadcast addresses. Special treatment may apply to /31 and /32, which are commonly used for point-to-point links and host routes.