Calculate network address, broadcast, host range, usable hosts, and subnet details from any IP and CIDR.
Quick Answer:A /24 subnet (255.255.255.0) provides 254 usable host addresses. The number of usable hosts = 2^(32-CIDR) - 2. For example, 192.168.1.0/24 gives hosts 192.168.1.1 through 192.168.1.254.
Usable Hosts
Calculating... hosts available
Network Address
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Broadcast Address
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First Usable Host
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Last Usable Host
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Subnet Mask
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Wildcard Mask
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IP Class
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Private / Public
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IP Address
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Subnet Mask
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Network Address
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In 2026, with IPv4 exhaustion well underway, efficient subnetting is more critical than ever. Use /30 or /31 for point-to-point links, /28 for small server VLANs, and /24 for standard office segments. Variable Length Subnet Masking (VLSM) lets you allocate exactly the right number of addresses to each segment, reducing waste. For cloud deployments (AWS, Azure, GCP), plan your VPC CIDR blocks carefully -- a /16 gives 65,534 addresses that can be subdivided into many subnets.
A subnet mask is a 32-bit number that divides an IP address into a network portion and a host portion. It uses consecutive 1-bits for the network part and 0-bits for the host part. For example, 255.255.255.0 (/24) means the first 24 bits identify the network and the last 8 bits identify hosts, allowing 254 usable addresses. The subnet mask is applied using a bitwise AND operation with the IP address to determine the network address.
CIDR (Classless Inter-Domain Routing) notation is a compact way to specify an IP address and its associated network mask. It is written as IP/prefix-length, such as 192.168.1.0/24. The number after the slash indicates how many bits of the 32-bit address are used for the network portion. A /24 means 24 network bits and 8 host bits, equivalent to subnet mask 255.255.255.0, providing 254 usable host addresses.
The number of usable hosts in a subnet is calculated as 2^(32-CIDR) - 2. The two subtracted addresses are the network address (all host bits 0) and the broadcast address (all host bits 1). For example, a /24 subnet has 2^8 - 2 = 254 usable hosts, a /25 has 126, a /28 has 14, and a /30 has only 2 usable hosts (commonly used for point-to-point links).