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CIDR to Subnet Mask Converter
Enter a CIDR prefix or a subnet mask to convert between the two notations.
How to use this tool
- 1Enter a CIDR prefix to see its subnet mask.
- 2Or enter a subnet mask to see its CIDR prefix.
- 3Both update instantly.
Frequently asked questions
Why do I need to convert between these?+
Some tools and configs use CIDR notation (/24), others use dotted-decimal (255.255.255.0) — this converts between the two formats.
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