NETWORK ENGINEERING TOOL

Subnet & Wildcard Mask Calculator.

Calculate IPv4 network details, subnet masks, Cisco wildcard masks, host ranges, broadcast addresses and RFC classifications from a CIDR network.

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INPUT

Enter an IPv4 network

Enter an IPv4 address with CIDR notation. The calculation automatically identifies the network boundary.

Example: 10.20.30.0/24

NETWORK ENGINEERING

Subnet mask vs. wildcard mask

A subnet mask identifies which portion of an IPv4 address represents the network and which portion represents hosts.

A wildcard mask is the inverse of the subnet mask. It is commonly used in Cisco IOS configurations, access-control lists and OSPF network statements.

Subnet Mask Identifies the network and host portions of an IPv4 address.
Wildcard Mask Inverse of the subnet mask, commonly used in Cisco networking configurations.
RFC Classification Identifies common IPv4 address ranges and their associated RFC references.
⚠ Responsible Use

This tool is intended for network engineering, education, network administration and authorized troubleshooting.

HOW TO USE

How to calculate a subnet and wildcard mask

  1. Enter an IPv4 network and CIDR.

    Type a network such as 10.20.30.0/24.

  2. Click Calculate Network.

    Submit the form to run the calculation.

  3. Review the results.

    The tool returns the network address, broadcast address, subnet mask, Cisco wildcard mask, usable host range, usable hosts, total addresses, prefix length and RFC address classification.

Subnet & Wildcard Mask FAQ

What is a wildcard mask?

A wildcard mask is the inverse of the subnet mask. It is commonly used in Cisco IOS access-control lists and OSPF network statements.

What is the difference between a subnet mask and a wildcard mask?

A subnet mask identifies the network and host portions of an address by marking network bits as 1. A wildcard mask inverts this, marking the bits Cisco should ignore when matching addresses.

What is CIDR notation?

A way of writing an IP network as an address followed by a slash and the number of bits used for the network portion, such as /24.

What information does this calculator provide?

Network address, broadcast address, subnet mask, wildcard mask, usable host range, usable hosts, total addresses, prefix length and RFC address classification.