What is CIDR notation?

CIDR (Classless Inter-Domain Routing) uses IP/prefix format like 192.168.1.0/24 where /24 indicates the subnet mask bits.

How do I calculate subnet size from CIDR?

Hosts = 2^(32-prefix) - 2. For /24: 2^8 - 2 = 254 usable hosts. Subtract 2 for network and broadcast addresses.

What's the difference between /24 and /16?

/24 gives 254 hosts (255.255.255.0 mask). /16 gives 65,534 hosts (255.255.0.0 mask). Smaller prefix = larger network.

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CIDR Calculator

Calculate IP address ranges and subnet information

Enter IP Address and CIDR

IP Address

CIDR Bits (/24)

/0/24/32

Common Subnets

About CIDR Calculator

What is CIDR Calculator?

Calculate IP address ranges, network and broadcast addresses, subnet masks, and available host counts from CIDR notation. Essential for network planning and troubleshooting.

Features & Benefits

CIDR to IP range conversion
Subnet mask calculation
Network/broadcast addresses
Available host count
IPv4 and IPv6 support
Subnet visualization

Frequently Asked Questions

What is CIDR notation?: CIDR (Classless Inter-Domain Routing) uses IP/prefix format like 192.168.1.0/24 where /24 indicates the subnet mask bits.
How do I calculate subnet size from CIDR?: Hosts = 2^(32-prefix) - 2. For /24: 2^8 - 2 = 254 usable hosts. Subtract 2 for network and broadcast addresses.
What's the difference between /24 and /16?: /24 gives 254 hosts (255.255.255.0 mask). /16 gives 65,534 hosts (255.255.0.0 mask). Smaller prefix = larger network.

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How to Calculate CIDR Subnets

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