Subnet Calculator
Learn how to use the 2network IPv4 Subnet Calculator to compute network addresses, broadcast addresses, host ranges, and CIDR notation.
Try Subnet Calculator →What It Does
The Subnet Calculator takes an IPv4 address and a CIDR prefix length (or subnet mask) and instantly computes the full subnet breakdown: network address, broadcast address, subnet mask, wildcard mask, first and last usable host, total IPs, usable host count, IP class, and whether the address is private or public.How to Use It
- Navigate to IP Tools → Subnet Calculator from the top menu.
- Enter an IPv4 address in the IP Address field (e.g.,
192.168.1.0). - Enter a CIDR prefix in the CIDR / Mask field (e.g.,
24) — you can also enter a full subnet mask like255.255.255.0. - Click Calculate or press Enter.
- View the results grid showing all computed values.
- Click the copy icon next to any value to copy it to your clipboard.
- Use Copy All to copy the entire result set as formatted text, or Download .txt to save it as a file.
Quick Presets
Click any of the preset buttons (/8, /12, /24, /25, /26, /27, /28, /30) to instantly populate and calculate common subnet sizes. These use standard private IP ranges as the base address.
Example: Planning a /26 Subnet
You need to allocate a subnet for a department of 50 users:
- Enter
10.10.5.0as the IP address. - Enter
26as the CIDR prefix. - Click Calculate.
Results show 64 total IPs with 62 usable hosts — enough for 50 users with room to grow. The network range is 10.10.5.0 to 10.10.5.63.
CIDR Reference Table
Below the calculator, a reference table lists every CIDR prefix from /8 to /32 with the corresponding subnet mask, wildcard mask, total IPs, and usable host count. This is useful for quick lookups without entering values.Use Cases
- Network design: Plan IP address allocation for VLANs and departments.
- Firewall rules: Determine the correct network/mask for ACL entries.
- Troubleshooting: Verify if two devices are on the same subnet.
- Documentation: Export subnet details for network diagrams and change requests.