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IPv4 Subnet and CIDR Calculator

IPv4 Subnet and CIDR Calculator

Calculate network, broadcast, host range, wildcard mask, and binary values from an IPv4 address and CIDR or netmask.

Focus mode

Enter CIDR as /24 or 24, or enter a netmask such as 255.255.255.0.

Subnet information

Network address
192.168.0.0/24
Broadcast address
192.168.0.255
First host
192.168.0.1
Last host
192.168.0.254
Netmask
255.255.255.0
Wildcard
0.0.0.255
Total addresses
256
Usable hosts
254
IP class
C
Scope
Private

Binary representation

IP
11000000.10101000.00000000.00001010
Netmask
11111111.11111111.11111111.00000000
Network
11000000.10101000.00000000.00000000
Broadcast
11000000.10101000.00000000.11111111
Integer (uint32)
3,232,235,530

Key features

  • Accepts CIDR prefix lengths from 0 to 32 or contiguous dotted-decimal netmasks.
  • Calculates network, broadcast, first and last host, and address counts.
  • Shows netmask, wildcard, traditional IP class, and a private, public, or special scope label.
  • Copies binary IP, mask, network, broadcast, and uint32 values.

How to use

  1. Enter an IPv4 address as four decimal octets.
  2. Provide the mask as /24, 24, or 255.255.255.0.
  3. Review subnet, host, and binary values and copy the fields you need.

Examples

  • Plan a subnet range

    Enter IPv4/CIDR to inspect network, broadcast, first-host, and last-host addresses.

  • Convert CIDR and masks

    Find the subnet mask and wildcard mask corresponding to a prefix length.

Privacy

IPv4 validation and 32-bit subnet calculations run in your browser; the tool does not send a network request to the entered address.

Requirements

Dotted netmasks must contain contiguous one-bits from the left. The tool reports two usable values for /31 and one for /32, and its class and scope labels are simplified classifications.

Common questions

Does it detect my public IP address automatically?
No. It calculates only the IPv4 address and CIDR prefix you enter and does not call an external IP service.
How is usable host count calculated?
Normal subnets exclude network and broadcast addresses. A /31 treats both point-to-point addresses as usable, and a /32 represents one usable address.

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