IPv4 Subnet Calculator (CIDR & Masks)
Calculates IPv4 subnet partitions, network ID, broadcast IP, usable address range, and total host capacity.
IPv4 CIDR Subnet Calculator & Address Allocator
Computes network ID, broadcast IP, usable host range, 32-bit subnet mask, and RFC classifications
Dynamic Subnet Address Space Allocation
Visual topology of Network ID, Default Gateway, Usable Host Pool, and Broadcast Address
32-Bit Binary Mask & Boundary Visualizer
Octet-by-octet breakdown showing Network bits (blue) vs Host bits (emerald)
What is IPv4 Subnetting?
Subnetting divides a larger IP network into smaller, more efficient subnetworks. CIDR (Classless Inter-Domain Routing) specifies the number of leading network bits using prefix notation (e.g. /24).
Formula & Step-by-Step Calculation
Network address and broadcast address are reserved.
Worked Step-by-Step Examples
Subnet 192.168.1.150 with CIDR /24
Common Real-World & Academic Use Cases
- ✓ Cloud VPC network architecture (AWS, Azure, GCP)
- ✓ Enterprise LAN DHCP scope configuration
- ✓ Firewall security rule access control lists
How to Use the IPv4 Subnet Calculator (CIDR & Masks)
Enter IP Address
Input standard IPv4 address.
Select CIDR Prefix
Choose /0 through /32.
Read Network Parameters
Inspect network ID, broadcast, and usable IP range.
Frequently Asked Questions
Q: Why are 2 addresses subtracted from total hosts?
The first address is reserved as the Network ID, and the last address is reserved as the Broadcast Address.