What does CIDR notation mean?

CIDR (Classless Inter-Domain Routing) writes an IP address followed by a prefix length, e.g. 192.168.0.0/24. The number after the slash is how many leading bits belong to the network portion.

How many hosts fit in a /24?

A /24 leaves 8 host bits, giving 256 addresses total. After reserving network and broadcast addresses, you typically have 254 usable host addresses.

Can I calculate broadcast and network IDs?

Yes. The calculator derives the network address, broadcast address, first and last usable host, and wildcard mask from the CIDR you enter.

Does it support IPv6?

This tool focuses on IPv4 CIDR. For IPv6 planning, use a dedicated IPv6 subnet calculator with 128-bit address support.

Is my data uploaded when I use CIDR Calculator?

No. CIDR Calculator runs entirely in your browser. Your input never leaves your device.

Why do admins use CIDR calculators?

They prevent overlapping subnets, size VLANs correctly, and document firewall rules and routing tables without manual bit math.

CIDR Calculator

Network Live

Calculate subnet ranges, network/broadcast addresses and host counts.

About this tool

CIDR Calculator — Calculate subnet ranges, network/broadcast addresses and host counts. Free, fast and private. Runs entirely in your browser at Quick Calci T

Examples

Common scenarios for the CIDR Calculator.

Classless /24

cidr: 192.168.1.0/24

254 usable hosts · network 192.168.1.0 · broadcast 192.168.1.255

Small /30 link

cidr: 10.0.0.0/30

2 usable hosts for point-to-point links.

Who uses the CIDR Calculator?

Common scenarios and audiences for this tool.

Network engineers

Use the tool for network engineers workflows without leaving the browser.

Cloud architects

Speed up cloud architects tasks with instant local processing.

DevOps teams

Handle devops teams checks during development or review.

Security analysts

Support security analysts with a private, signup-free utility.

Students

Ideal for students when you need quick, repeatable results.

Frequently asked questions

Everything you need to know about the CIDR Calculator.