What is CIDR notation?

CIDR notation writes an IPv4 address with a slash and a prefix length, such as 192.168.1.0/24. The number after the slash is how many bits belong to the network portion; the rest are host bits.

How do I calculate a /24 network?

A /24 uses 24 network bits and 8 host bits. Enter 192.168.1.0/24 in this calculator to see mask 255.255.255.0, network 192.168.1.0, broadcast 192.168.1.255, and 254 usable hosts.

How many hosts are in a /24 subnet?

A /24 has 256 total addresses. After you reserve the network and broadcast addresses, 254 usable hosts remain.

How do I convert CIDR to a subnet mask?

Write prefix-length ones from the left, fill the rest with zeros, then convert each octet to decimal. /24 becomes 255.255.255.0. This tool shows the dotted mask and binary mask together so you can check your conversion.

Can I calculate IPv4 network and broadcast addresses?

Yes. Enter any valid IPv4 CIDR string and the calculator returns the network address, broadcast address, and usable host range for that block.

What is CIDR Calculator?

A CIDR calculator takes an IPv4 address written with a prefix (for example 10.0.0.0/8) and works out the matching subnet mask, host counts, and network boundaries. This one is free and runs in your browser.

How does the CIDR Calculator work?

It reads the prefix length, builds the matching 32-bit mask, applies that mask to the address to find the network ID, then derives broadcast, usable range, and host counts from the remaining host bits.

How do I use the CIDR Calculator?

Type an address with a slash prefix such as 172.16.0.0/12, or pick an example button. Results update as you type, no account and no download.

Is this CIDR Calculator free to use?

Yes. It is free for beginners, CCNA students, network engineers, and anyone practising subnetting. No sign-up is required.

Can I use the CIDR Calculator on mobile?

Yes. The page works in a mobile browser, so you can check CIDR maths on a phone or tablet as well as on a desktop.

Free CIDR Calculator Online, IPv4 CIDR Notation Tool

Free CIDR Calculator Online, IPv4 CIDR Notation Tool | Binary Tech