Subnet & CIDR Toolkit

Calculate IPv4 subnet masks, usable address ranges and broadcast addresses. Check IP membership, split subnets, and convert IP ranges to CIDR in your browser.

Three tools for IPv4 network planning

Calculate a subnet from an IPv4 address and prefix or subnet mask, check which CIDR ranges contain an address, and convert an address range into CIDR blocks. Advanced details include binary masks and equal-size subnet splitting.

How to use the subnet toolkit

  1. Choose Subnet calculator, IP in CIDR, or IP range to CIDR.
  2. Enter your IPv4 values and calculate. The initial 192.168.1.10/24 value is an example.
  3. Review and copy the result. A /24 normally contains 256 addresses and 254 usable host addresses; /31 point-to-point links and /32 host routes use different rules.

Local calculations and scope

IPv4 calculations run in your browser without sending addresses to a lookup service. CIDR membership describes an address range; it does not test connectivity or evaluate firewall rule order. IPv6 subnet calculations are not included.