What it does: The Subnet Calculator accepts an IPv4 address and a CIDR prefix (or equivalent subnet mask) and instantly returns the network address, first usable host, last usable host, broadcast address, and total number of hosts. It is designed for quick on‑the‑go calculations on desktop or mobile browsers.
Key features:
- Text‑input: Type the IP address and CIDR or mask directly.
- Real‑time preview: Results appear as you type, no extra button needed.
- One‑click copy: Copy any result field with a single icon.
- Safe input validation: Invalid octets, out‑of‑range prefixes, and non‑numeric characters are rejected before calculation.
Basic usage steps: 1. Enter the IP address in the first field (e.g., 192.168.10.0). 2. Provide the CIDR prefix (e.g., /24) or select a subnet mask from the dropdown. 3. Press Enter or click the Calculate button; the preview updates automatically. 4. Copy needed values using the copy icons next to each result.
Example: Input = 192.168.10.0/24 → Network = 192.168.10.0, First host = 192.168.10.1, Last host = 192.168.10.254, Broadcast = 192.168.10.255, Hosts = 254.
Essential notes:
- Only IPv4 addresses are supported; IPv6 is out of scope.
- The validator blocks octets >255 and prefixes outside 0‑32.
- Results are displayed in decimal; convert to binary manually if required.
- Use the copy function to avoid transcription errors when documenting networks.
Ready to calculate? Calculate Subnet
FAQ
Can the Subnet Calculator handle IPv6 addresses?
No. The current version supports IPv4 only; IPv6 support may be added in a future release.
What happens if I enter an invalid IP address?
The tool’s safe input validation will highlight the error and prevent calculation until the address is corrected.
Is there a limit to the number of calculations I can perform?
No. The calculator is free and unlimited for all users.
Can I copy individual result fields?
Yes. Each output line has a copy icon that copies the value to your clipboard with one click.