CIDR Subnet Splitter
Split a parent CIDR block into equal subnets. Enter 192.168.0.0/16 and target /24 for a full table of network, broadcast, and host ranges.
Added Jun 1, 2026
Input
Result
Enter a value for parent cidr block to see your result.
How it works
Divides a parent CIDR block into equal subnets of a chosen prefix length. Lists every resulting network, broadcast address, host range, and usable host count — ideal for VLAN planning, cloud VPC subnet design, and network documentation.
Step by step
- 01Enter the parent network in CIDR notation (must be a network address, e.g. 192.168.0.0/16).
- 02Set the target prefix length — it must be longer (larger number) than the parent prefix.
- 03The tool generates a table of all resulting subnets with network, broadcast, and host details.
Examples
Split /16 into /24 subnets
A /16 split into /24 yields 256 subnets of 254 hosts each — typical VLAN design.
Inputs
- Parent CIDR block:
- 192.168.0.0/16
- Target prefix length:
- 24
Result
- Total subnets:
- 256
- Summary:
- 256 equal /24 subnets from 192.168.0.0/16.
Split /24 into /26 subnets
Dividing a /24 into four /26 subnets gives 62 usable hosts per segment.
Inputs
- Parent CIDR block:
- 10.10.10.0/24
- Target prefix length:
- 26
Result
- Total subnets:
- 4
- Summary:
- 4 equal /26 subnets from 10.10.10.0/24.
Frequently asked questions
How do I split a /16 into /24 subnets?
Enter 192.168.0.0/16 as the parent and 24 as the target prefix. The difference (24 − 16 = 8) means 2⁸ = 256 subnets. Each /24 has 254 usable host addresses.
Why must the parent be a network address?
CIDR blocks are defined from the network address — the address with all host bits set to zero. 10.0.0.0/8 is valid; 10.0.0.5/8 is not, because .5 has host bits set. Use the Subnet Calculator to find the network address first.
How many subnets can I create?
The number of subnets is 2^(target prefix − parent prefix). Splitting /8 into /16 creates 256 subnets; /8 into /24 creates 65 536. The table shows up to 512 rows for performance.