What is CIDR notation?

CIDR (Classless Inter-Domain Routing) notation expresses an IP address and its subnet mask as a single string like 192.168.1.0/24, where /24 means the first 24 bits are the network portion.

How many usable hosts does a /24 subnet have?

A /24 subnet has 256 addresses total. Subtracting the network address and broadcast address leaves 254 usable host addresses.

Does it support IPv6?

The calculator focuses on IPv4 subnetting. IPv6 subnetting follows the same binary principles but with 128-bit addresses.

Best Free Online Subnet Calculator

Subnetting is a fundamental networking skill, but calculating network ranges, broadcast addresses, subnet masks, and usable host counts by hand is slow and error-prone. devtoolkit.sh's Subnet Calculator takes any IPv4 address with a CIDR prefix length and instantly computes the network address, broadcast address, subnet mask, wildcard mask, and number of usable hosts. It also lists common subnet sizes for quick reference when designing IP address plans. Whether you are configuring cloud VPC subnets, writing firewall rules, or studying for a networking certification, this tool gives you accurate results instantly without requiring network engineering expertise.

Network Address192.168.1.0

Subnet Mask255.255.255.0

Wildcard Mask0.0.0.255

Broadcast Address192.168.1.255

First Usable Host192.168.1.1

Last Usable Host192.168.1.254

Total Hosts256

Usable Hosts254

CIDR Prefix/24

FAQ

What is CIDR notation?: CIDR (Classless Inter-Domain Routing) notation expresses an IP address and its subnet mask as a single string like 192.168.1.0/24, where /24 means the first 24 bits are the network portion.
How many usable hosts does a /24 subnet have?: A /24 subnet has 256 addresses total. Subtracting the network address and broadcast address leaves 254 usable host addresses.
Does it support IPv6?: The calculator focuses on IPv4 subnetting. IPv6 subnetting follows the same binary principles but with 128-bit addresses.