- Enter an IPv4 address (e.g. 192.168.1.100).
- Enter the prefix length (e.g. 24) or subnet mask (e.g. 255.255.255.0).
- View the calculated network address, broadcast, first and last host, and total hosts.
Subnet Calculator
Calculate subnet details from an IPv4 address and prefix length or subnet mask.
How to Use This Tool
Learn More About Subnet Calculator
Understanding Subnets
A subnet divides a larger network into smaller segments. The subnet mask (or prefix length) defines how many bits belong to the network and how many to the host. The network address is the first address in the range; the broadcast address is the last. Usable host addresses are between the first host and the last host (inclusive).
Related Tools
- CIDR to IP Range converts CIDR notation to first and last IP.
- IP Validator checks if an address is valid IPv4 or IPv6.
About Subnet Calculator
The Subnet Calculator helps network administrators and developers determine key subnet information from an IPv4 address and prefix length or subnet mask. It computes the network address, broadcast address, first and last usable host, and the total number of usable hosts—essential for planning and configuring networks.
Calculate IPv4 subnet details from an IP and prefix or mask.
- Platform
- Web-based
- Cost
- Free
- IPv4 only
- Yes
Examples
Class C subnet
Calculate a /24 subnet for 192.168.1.0.
Input
IP: 192.168.1.0, Prefix: 24
Output
Network: 192.168.1.0, Broadcast: 192.168.1.255, Usable hosts: 254
Small subnet
Calculate a /28 subnet.
Input
IP: 10.0.0.1, Prefix: 28
Output
Network: 10.0.0.0, First host: 10.0.0.1, Last host: 10.0.0.14, Broadcast: 10.0.0.15, Usable: 14
Features
Prefix or Mask
Input either CIDR prefix (e.g. /24) or dotted subnet mask.
Full Subnet Info
Shows network, broadcast, first/last host, and host count.
Instant Results
Calculations run in the browser with no server required.
Use Cases
- Plan subnets and allocate IP ranges.
- Configure firewalls and ACLs with correct ranges.
- Verify network and broadcast addresses for an IP and mask.
- Learn how subnetting works with real examples.
Frequently Asked Questions
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