Calculate IPv4 subnets instantly with our free subnet calculator. Enter any IP address and CIDR notation to get network address, broadcast address, usable IP range, subnet mask, wildcard mask, and complete subnet details.
192.168.1.0/24 (Class C) · 10.0.0.0/8 (Class A) · 172.16.0.0/12 (Class B)
Get network address, broadcast, usable IPs, and subnet mask details
Calculate network subnets in seconds. Enter an IP address and CIDR prefix to instantly get comprehensive subnet information including network address, broadcast address, and usable host range.
Get all essential subnet details in one place: network address, broadcast address, subnet mask, wildcard mask, first and last usable IPs, total hosts, IP class, and binary representations.
Our calculator uses standard CIDR notation (Classless Inter-Domain Routing) for modern network design. Simply enter IP/prefix like 192.168.1.0/24 for instant results.
Automatically identifies IP address classes (A, B, C, D, E) and determines whether your IP is private, public, or loopback for better network planning.
Quickly copy all subnet calculations to clipboard for documentation, reports, or configuration files. Perfect for network administrators and IT teams.
View IP addresses, subnet masks, and network addresses in binary format to understand how subnetting works at the bit level.
IP subnetting is the process of dividing a network into smaller sub-networks (subnets) to improve network performance, security, and management. Subnetting allows organizations to efficiently use IP address space and create logical network segments.
CIDR (Classless Inter-Domain Routing) notation represents IP networks using an IP address followed by a slash and prefix length (e.g., 192.168.1.0/24). The prefix length indicates how many bits are used for the network portion of the address.
A subnet mask defines which portion of an IP address is the network and which is the host. A wildcard mask is the inverse of a subnet mask, commonly used in Cisco ACLs and routing configurations.
Private IP addresses are reserved for internal networks and not routable on the internet:
Home and small office networks typically use 192.168.1.0/24, providing 254 usable IP addresses. This is the default configuration for most consumer routers.
Growing businesses often use /22 or /23 subnets to accommodate 500-1000 devices across multiple departments while maintaining efficient IP address management.
Large organizations use larger subnets like /16 or /20 to support thousands of devices across multiple locations, VLANs, and network segments.
Router-to-router connections use /30 (2 usable IPs) or /31 (2 IPs for point-to-point) subnets to minimize IP address waste on network infrastructure links.
Data centers commonly use /25 to /27 subnets to segment servers, storage, and management networks while maintaining security boundaries.
Plan network architecture by calculating available IP ranges, determining optimal CIDR prefixes, and designing subnet hierarchies for scalability.
Calculate subnet ranges for Virtual LANs (VLANs) to segment network traffic by department, function, or security requirements in enterprise environments.
Manage IP address allocation across your organization by tracking subnet usage, identifying available address space, and preventing IP conflicts.
Generate accurate subnet masks and wildcard masks for configuring routers, switches, firewalls, and access control lists (ACLs).
Design cloud network architectures in AWS, Azure, or Google Cloud by calculating VPC subnets, availability zones, and IP addressing schemes.
Diagnose network connectivity problems by verifying IP addresses are in the correct subnet range and checking for subnet misconfigurations.
Always allocate larger subnets than currently needed to accommodate future expansion. It's easier to use a /23 instead of multiple /24s later.
Document subnet purposes clearly (e.g., 192.168.10.0/24 for servers, 192.168.20.0/24 for workstations) to simplify network management.
Ensure subnets don't overlap when designing network hierarchies. Use subnet calculators to verify boundaries and prevent routing conflicts.
Reserve the first few IPs in each subnet for network infrastructure (routers, switches, gateways) and the last few for future expansion.
Maintain accurate documentation of all subnet assignments, VLAN mappings, and IP address allocations using network diagrams and IP address management tools.
Use subnetting to create security zones separating trusted networks (corporate), DMZ (public-facing services), and guest networks for better security control.
A /24 subnet provides 256 total IP addresses (254 usable) and uses subnet mask 255.255.255.0, suitable for small networks. A /16 subnet provides 65,536 total IP addresses (65,534 usable) with subnet mask 255.255.0.0, designed for large enterprise networks.
For any subnet, usable hosts = (2^(32-CIDR)) - 2. We subtract 2 because the network address and broadcast address cannot be assigned to hosts. For /24: (2^8) - 2 = 254 usable hosts.
Wildcard masks are the inverse of subnet masks, commonly used in Cisco router configurations for access control lists (ACLs) and OSPF routing. For subnet mask 255.255.255.0, the wildcard mask is 0.0.0.255.
No, 192.168.1.0 is the network address in a /24 subnet and cannot be assigned to a host. The first usable IP is 192.168.1.1. Similarly, 192.168.1.255 is the broadcast address and also cannot be assigned.
A /32 CIDR represents a single host IP address with subnet mask 255.255.255.255. It's used for specific host routes, loopback addresses, or when you need to reference exactly one IP address.
To subnet a Class C network (e.g., 192.168.1.0/24), increase the CIDR prefix beyond /24. For example, /25 creates 2 subnets with 126 hosts each, /26 creates 4 subnets with 62 hosts each, and /27 creates 8 subnets with 30 hosts each.
The subnet mask for /22 is 255.255.252.0, which provides 1,024 total IP addresses (1,022 usable hosts). This is commonly used for medium-sized networks requiring 500-1000 devices.
Private IP addresses (10.x.x.x, 172.16-31.x.x, 192.168.x.x) are not routable on the public internet, providing security and allowing multiple organizations to use the same addresses internally. Network Address Translation (NAT) enables private IPs to access the internet.
The network address is the first IP in a subnet and identifies the network itself. The broadcast address is the last IP and is used to send messages to all hosts in the subnet. Neither can be assigned to individual devices.
By extending the CIDR prefix, you can create: /25 = 2 subnets, /26 = 4 subnets, /27 = 8 subnets, /28 = 16 subnets, /29 = 32 subnets, /30 = 64 subnets. Each subdivision reduces available hosts per subnet.