Subnet Mask Calculator

Computes IPv4 subnet details—mask, network address, broadcast address, usable host range, and address count—from an IP address and prefix length.

Runs locally in your browser

Network and IP address calculator

Show the network address, broadcast address, and first and last usable host addresses.

CIDR prefix length is the number of leading network bits in the subnet mask, such as /24.

Subnet mask converter (prefix length and dotted decimal)

Network/node calculator

Decimal subnet mask countercalculator

Decimal subnet mask converter

Calculate an IP address (reverse)

Network and IP address calculator

Network ListNetwork 0.0.0.0, mask 0.0.0.0"×

Network Host Radio Address
Start End
0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0
0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0
0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0
0.0.0.0 0.0.0.0 0.0.0.0 0.0.0.0

Calculate a subnet from the required host count

TCP/IP Progressive Converter

Convert a prefix length or subnet mask into the number of total and usable IPv4 addresses.

IP Group Address Range

A valid subnet mask has contiguous 1 bits followed by contiguous 0 bits; non-contiguous masks are invalid for CIDR.

224.0.0.0 - 224.0.0.255 Prominent multicast address, control channel

224.0.1.0 - 238.255.255.255 Global (Internet wide) group addresses

239.0.0.0 - 239.255.255.255 Local overcast address

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