ToolsFaction Online Tool
Subnet Mask Calculator
Convert a CIDR prefix into IPv4 mask and host information.
Convert CIDR prefixes to IPv4 subnet masks, wildcard masks, host bits and address counts online.
About This Tool
ToolsFaction Subnet Mask Calculator converts a CIDR prefix into its IPv4 subnet mask and related network values. It is useful for network planning, documentation, firewall rules and certification practice.
How to Use
- Enter a CIDR prefix from 0 to 32.
- Select Calculate.
- Review the subnet and wildcard masks.
- Use the address and host counts as needed.
Example
Enter 24 to calculate 255.255.255.0 and the related address capacity.
Frequently Asked Questions
What is a CIDR prefix?
It indicates how many bits of an IPv4 address belong to the network portion.
What is a wildcard mask?
It is the bitwise inverse of the subnet mask and is used by some network configurations.
Does this scan a network?
No. It only performs mathematical calculations.
Does it support IPv6?
This tool is focused on IPv4.
Free to UseNo hidden fees
No Sign-UpStart instantly
Browser-BasedNothing to install
Privacy FriendlyBuilt for simple use