IPv4 Subnet & CIDR Netmask Calculator
Calculate network address, broadcast, and usable host count from CIDR.
Tool inputs stay in your browser · optional AI search sends your query
Good to know: Calculates binary subnets, network boundaries, and host allocation ranges from IPv4 CIDR blocks.
How to use it (step by step)
- 1Fill in the boxes: “IP Address”, “CIDR Prefix (/1 to /32)”. Example numbers are already there so you can see how it works; replace them with yours.
- 2The result updates instantly as you type (on a phone it is below the boxes).
- 3The bold line is the main answer. Tap Copy next to any value to copy it.
Words to know
- IPv4 / IPv6
- Two versions of IP addresses. IPv4 looks like 192.168.1.1 (running out); IPv6 is the newer, much longer kind like 2001:db8::1.
- Subnet / CIDR
- A way to split networks into blocks. 192.168.1.0/24 means 256 addresses from 192.168.1.0 to 192.168.1.255.
- Masking
- Hiding most of a number with dots or stars, like •••• 4242, so it cannot be misused.
- Hex / binary
- Other ways of writing numbers. Binary uses only 0 and 1; hex uses 0–9 and A–F.
- IP address
- The address of a device on the internet, like a house number for your connection. Websites need it to send pages back to you.
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