Subnet Mask Calculator

Enter a CIDR prefix length or specify your required number of hosts to instantly calculate the correct subnet mask in dotted-decimal, binary, and hexadecimal formats. Find the optimal mask size for your network, view usable host ranges, and convert between subnet mask notations — all in one place. Use the subnet calculation tool to determine subnet boundaries, host capacity, and address ranges across IPv4 and IPv6 networks.

/
255.255.255.0

Subnet Mask Reference Table

CIDRSubnet MaskWildcard MaskTotal IPsUsable Hosts

Related Network Tools

Explore these related tools for subnet calculation and IP address management.

Additional networking calculators for IP address planning and network analysis. The cidr calculator handles any prefix from /0 to /32 and returns all derived subnet values alongside binary representation.

More tools to support network design, addressing, and subnet troubleshooting. The ip address validator validates both IPv4 dotted-decimal and IPv6 colon-separated formats in a single check.

Comments & Feedback

Share your experience or ask questions about this tool