Subnet Calculator
Free subnet mask calculator — convert CIDR to subnet mask, calculate network ranges, and plan IP subnets instantly in your browser.
Subnet Calculator
Enter an IP address and CIDR prefix to get the full subnet breakdown — network, broadcast, host range, and more.
CIDR to Subnet Mask
Convert CIDR notation (e.g. /24) to a dotted-decimal subnet mask and see all CIDR prefixes at a glance.
Subnet Mask to CIDR
Convert a dotted-decimal subnet mask (e.g. 255.255.255.0) to CIDR prefix length.
About Subnet Calculator
Plan your network subnets with free, instant calculators. Convert between CIDR notation and subnet masks, calculate host ranges, and understand network boundaries — all in your browser with no data sent to any server.
Whether you're a network engineer configuring VLANs, a cloud architect planning VPC subnets, or a student studying for the CCNA — these tools give you the answers you need in seconds.