Networking & IT Tools
CIDR to Subnet Mask Converter
Enter a CIDR prefix or a subnet mask to convert between the two notations.
/24 = 255.255.255.0
= /24
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.