IP CIDR Calculator – Free Subnet Calculator

Calculate network address, broadcast, host range from IP and CIDR prefix. Binary visualization of network and host bits.

Try it Free →

Features

🌐

Full Subnet Info

Network address, broadcast address, first/last usable host, total hosts, and wildcard mask.

📊

Binary Visualization

Visual breakdown of network bits vs host bits in binary format.

🏷️

IP Class Display

Shows IP class (A/B/C/D/E) and whether it's public, private, or reserved.

🔢

CIDR Prefix Support

Supports /0 to /32 prefix lengths (IPv4). Also accepts /0 to /128 for IPv6.

🔒

Privacy First

All calculations are local JavaScript. No network requests.

🔄

IPv4 & IPv6

Works with both IPv4 and IPv6 addresses.

How to Use

1

Enter IP Address

Type an IP address (e.g., 192.168.1.100).

2

Enter Prefix

Enter CIDR prefix length (e.g., 24 for /24 = 255.255.255.0).

3

View Results

See all subnet information including network, broadcast, and host range.

4

Check Binary

View the binary breakdown to understand network vs host bit division.

Frequently Asked Questions

What is CIDR notation?
CIDR (Classless Inter-Domain Routing) notation combines an IP address with a prefix length: e.g., 192.168.1.0/24. The /24 means the first 24 bits are the network portion.
How do you calculate the subnet mask?
The subnet mask has 1s for network bits and 0s for host bits. For /24, the mask is 255.255.255.0 (24 ones, 8 zeros).
What is a private IP address?
Private IP ranges: 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16. These are reserved for private networks and not routable on the public internet.
How many usable hosts in a /24 network?
A /24 has 256 addresses total (2^8). Subtract 2 for network address and broadcast = 254 usable hosts.
Is my data sent to a server?
No. All IP calculations are done locally in the browser using JavaScript. No network requests are made.

← Back to pudone! home