Calculate IPv4 Broadcast Information
Use a CIDR prefix, a subnet mask, or both. If both are entered, they must match.
Example Data Table
| IPv4 Address | CIDR | Subnet Mask | Network Address | Broadcast Address | Host Range |
|---|---|---|---|---|---|
| 192.168.1.67 | /24 | 255.255.255.0 | 192.168.1.0 | 192.168.1.255 | 192.168.1.1 - 192.168.1.254 |
| 10.12.48.200 | /20 | 255.255.240.0 | 10.12.48.0 | 10.12.63.255 | 10.12.48.1 - 10.12.63.254 |
| 172.16.5.9 | /28 | 255.255.255.240 | 172.16.5.0 | 172.16.5.15 | 172.16.5.1 - 172.16.5.14 |
| 203.0.113.130 | /26 | 255.255.255.192 | 203.0.113.128 | 203.0.113.191 | 203.0.113.129 - 203.0.113.190 |
Formula Used
The broadcast address is the last IPv4 address inside the subnet. It is found by combining the network bits with all host bits set to 1.
Network Address = IP Address AND Subnet Mask
Wildcard Mask = 255.255.255.255 - Subnet Mask
Broadcast Address = Network Address OR Wildcard Mask
Total Addresses = 2^(32 - CIDR)
Usable Hosts = Total Addresses - 2 for most subnets.
Special cases: /31 and /32 behave differently because point-to-point and single-address networks do not follow the usual host rule.
How to Use This Calculator
- Enter a valid IPv4 address such as 192.168.10.44.
- Provide a CIDR prefix like /24, a subnet mask, or both.
- Click Calculate Broadcast Address.
- Review the network address, broadcast address, host range, binary values, and classification.
- Use the CSV or PDF buttons to export the generated results.
- Inspect the Plotly graph to see where the entered IP sits inside the subnet.
FAQs
1. What is a broadcast address?
A broadcast address is the last IPv4 address in a subnet. Devices use it to send a message to every host on that local network segment.
2. How is the broadcast address calculated?
First calculate the network address using the IP and subnet mask. Then set every host bit to 1. The resulting value is the broadcast address.
3. Why does the calculator show a wildcard mask?
The wildcard mask is the inverse of the subnet mask. It helps describe which bits are available for hosts and is commonly used in routing and access control rules.
4. Can I use either CIDR or subnet mask?
Yes. You can enter only the CIDR, only the subnet mask, or both. If both are entered, the page checks that they represent the same subnet size.
5. Why are /31 and /32 special?
/31 networks are often used on point-to-point links. /32 identifies one exact address. These cases do not follow the normal network, host, and broadcast assumptions.
6. What does usable host count mean?
Usable host count is the number of addresses typically assignable to devices. In common subnets, it excludes the network address and the broadcast address.
7. Does this calculator support IPv6?
No. This version is designed for IPv4 broadcast calculations. IPv6 does not use broadcast addressing in the same way IPv4 does.
8. Why is binary output useful?
Binary output makes subnet logic easier to verify. It helps you see which bits belong to the network portion and which bits belong to the host portion.