Subnet Mask Converter
Convert between dotted subnet mask, CIDR prefix length and wildcard mask.
| CIDR prefix | /24 | |
| Subnet mask | 255.255.255.0 | |
| Wildcard mask | 0.0.0.255 |
Pick an input format and get the matching CIDR prefix, dotted subnet mask and wildcard mask.
How to use
- Choose whether your value is a prefix, mask or wildcard.
- Type the value, e.g. 24 or 255.255.255.0.
- Read all three equivalent forms.
Frequently asked questions
- What is a contiguous mask?
- A valid subnet mask has all its 1 bits on the left with no gaps, like 255.255.240.0. A value like 255.0.255.0 is not a valid mask.
- How do prefix and mask relate?
- The prefix is simply the count of leading 1 bits in the mask: /24 means 24 ones, which is 255.255.255.0.