YurlieIPv4 Subnet Calculator
Split any parent IPv4 network block into equal subnets by selecting a new CIDR prefix.
IPv4 Subnet Splitting Reference Table
When splitting a parent CIDR block, each increment in prefix length doubles the number of created subnets while halving the host capacity of each subnet:
| Parent CIDR | New Subnet Prefix | Number of Subnets | Usable Hosts / Subnet | Subnet Mask |
|---|---|---|---|---|
/24 | /25 | 2 | 126 hosts | 255.255.255.128 |
/24 | /26 | 4 | 62 hosts | 255.255.255.192 |
/24 | /27 | 8 | 30 hosts | 255.255.255.224 |
/24 | /28 | 16 | 14 hosts | 255.255.255.240 |
/24 | /30 | 64 | 2 hosts | 255.255.255.252 |
/16 | /24 | 256 | 254 hosts | 255.255.255.0 |
Frequently Asked Questions
How does IPv4 Subnet Splitting work?
Subnetting divides a larger IPv4 network block into smaller subnets by borrowing bits from the host portion of the IP address. Borrowing 1 bit splits the network into 2 subnets; borrowing 2 bits splits it into 4 subnets, and so on.
What is the difference between CIDR Calculator and Subnet Calculator?
A CIDR Calculator analyzes a single IP address block (e.g. 192.168.1.0/24) to find its mask, network ID, and usable hosts. A Subnet Calculator splits a parent network into multiple smaller sub-networks (e.g. splitting a /16 into sixteen /20 subnets).
What is Variable Length Subnet Masking (VLSM)?
VLSM allows network engineers to allocate subnets of non-equal sizes within the same network block, optimizing IP address space based on actual host capacity requirements.
Why are 2 IP addresses unusable in each subnet?
In standard IPv4 networking, the first IP address (all host bits 0) is reserved as the Network Address, and the last IP address (all host bits 1) is reserved as the Broadcast Address.