IP & Subnet Tools
Subnet Mask Converter
Enter a prefix (/24), a netmask (255.255.255.0), and get all forms.
📖 New to this? Read Understanding Subnets and Subnet Masks.
❓ Frequently Asked Questions
What is the Subnet Mask Converter used for?
Convert between CIDR prefix, dotted-decimal netmask, and wildcard mask.
Is the Subnet Mask Converter free and private?
Yes — it's completely free and runs entirely in your browser. Whatever you enter stays on your device and is never uploaded to any server.
Do I need to install anything to use the Subnet Mask Converter?
No. It works in any modern web browser on desktop, tablet, or phone — no downloads, no browser extensions, and no account required.