Subnet Mask Converter
Convert CIDR prefix to subnet mask, wildcard and host count. Free, private and instant.
About the Subnet Mask Converter
A prefix like /24 is shorthand for a subnet mask such as 255.255.255.0. The wildcard mask is its inverse and is used in some firewall rules.
When to use it
Use it when configuring routers, cloud networks or access lists, and to count the usable hosts in a subnet.
How to use the Subnet Mask Converter
- Enter or paste your input in the fields above.
- The result updates as you type, or press Run.
- Press Copy to copy the output.
Frequently asked questions
Is the Subnet Mask Converter free?
Yes. It is completely free, with no signup and no usage limits.
Is my data uploaded anywhere?
No. Everything runs locally in your browser, so what you type never leaves your device.
Does the Subnet Mask Converter work on mobile?
Yes. The tool is responsive and works on phones, tablets and desktops.
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