How do I find the subnet mask from CIDR?

Count the prefix as leading ones in a 32-bit mask, then convert to dotted decimal. /24 becomes 255.255.255.0. Enter /24 here and the calculator shows the dotted mask and binary form together.

What is the subnet mask for /24?

The subnet mask for /24 is 255.255.255.0. It uses 24 network bits and leaves 8 host bits (256 addresses, 254 usable).

How many hosts does each subnet support?

Usable hosts equal 2^(32 − prefix) − 2 for standard LAN masks (/0 to /30). This calculator shows usable hosts and total addresses for the mask you enter.

How is a subnet mask calculated?

You place ones for every network bit and zeros for every host bit, then write each 8-bit group as a decimal octet. Contiguous ones are required, a mask such as 255.0.255.0 is invalid.

Can this calculate network and broadcast addresses?

Yes. Add an IPv4 address alongside the mask or CIDR prefix and the tool returns network address, broadcast address, and the usable host range.

What is Subnet Mask Calculator?

It is a free online tool that converts between dotted subnet masks and CIDR notation, reports host capacity, and can derive network boundaries for an IPv4 address.

How does the Subnet Mask Calculator work?

It parses your mask or prefix, validates that the bit pattern is contiguous, builds the matching CIDR and binary mask, then optionally applies the mask to an IP to find network and broadcast addresses.

How do I use the Subnet Mask Calculator?

Type a mask such as 255.255.255.240 or a prefix such as /28. Add an IP if you need network and broadcast. Results update as you type on desktop or mobile.

Is this Subnet Mask Calculator free to use?

Yes. It is free online with no registration, suitable for home networks, IT students, and day-to-day network administration checks.

Can I use the Subnet Mask Calculator on mobile?

Yes. The calculator works in mobile browsers, so you can convert masks and check host counts away from your desk.

Free Subnet Mask Calculator Online, CIDR & IPv4 Mask Tool

Free Subnet Mask Calculator Online, CIDR & IPv4 Mask Tool | Binary Tech