IPv4 Subnet Calculator

Network address, broadcast, host range, and masks from CIDR.

About this tool

Enter an IPv4 address with a prefix length (CIDR) and get network, broadcast, usable host range, subnet mask, and wildcard mask. Built for firewall rules, VPC planning, and quick CIDR math.

What you get

Network and broadcast addresses
First and last usable host
Subnet mask and wildcard mask
Total and usable host counts
Common private-range presets (/24, /16, …)

How to use

Type a CIDR like 192.168.1.10/24 or pick a preset. Results update live — copy any value into your config.

Example

Plan VLANs, ACLs, and cloud security groups from CIDR notation.

Input

192.168.10.0/26

Output

Network: 192.168.10.0
Netmask: 255.255.255.192
Hosts: 62 usable (192.168.10.1 – 192.168.10.62)
Broadcast: 192.168.10.63

FAQ

How to calculate subnet from CIDR notation?

Enter an IPv4 address with prefix length like 192.168.1.10/24 to get network address, broadcast, mask, and host range instantly.

What is the broadcast address for a subnet?

It is the last address in the network—shown alongside the network address and usable host bounds.

How many usable hosts in a /24 network?

A /24 has 256 addresses; typically 254 are usable for hosts after reserving network and broadcast addresses.

How to find subnet mask from prefix length?

Enter the CIDR prefix and read the dotted-decimal subnet mask and wildcard mask in the results table.

How to calculate VLSM subnets from one network block?

Start with your parent CIDR, then divide prefix lengths to size subnets for VLANs, DMZ, and point-to-point links.

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