IPv4 Subnet Calculator
Input
About the Ipv4 Subnet Calculator
Calculate IPv4 subnet information: network address, broadcast address, usable host range, and mask in decimal and CIDR.
Enter an IP address and subnet mask to get all subnet details. Essential for network engineering and CCNA study.
How to use
- Enter an IP address.
- Enter the subnet mask or CIDR.
- Review the calculated subnet details.
Frequently Asked Questions
What is CIDR notation? ▾
CIDR (Classless Inter-Domain Routing) represents the subnet mask as a slash followed by the number of network bits. For example, /24 means 24 network bits (255.255.255.0 mask).
How many usable hosts are in a /26? ▾
62 — a /26 leaves 6 host bits (2^6 = 64 addresses), minus the network and broadcast addresses. The calculator shows ranges, broadcast, and usable count for any mask.
How do I split a /24 into four equal subnets? ▾
Borrow 2 bits → /26 each: .0/26, .64/26, .128/26, .192/26 with 62 usable hosts apiece. The calculator lists every range when you plan the split.
Why subtract 2 addresses from every subnet? ▾
The first address identifies the network and the last is the broadcast — neither is assignable to a host.