vlsm calculator
A fixed /24 would hand the same 254-host range to a sales department and a 2-endpoint link alike; VLSM (Variable Length Subnet Mask) fixes that by picking a different prefix for each need inside the same block.
This is the first block allocated because it is the largest request; 12 of the 62 available addresses go unused, the natural slack of rounding 50 up to the nearest power of 2.
The block starts at .64, right after the previous block .63 broadcast, with no address skipped between the two; that is how sequential allocation avoids fragmentation.
It is the last of the four blocks, with 0 wasted addresses because the 6 requested exactly matches the 6 usable ones a /29 offers; 136 free addresses remain from .120 to .255 for later growth.
Yes. It helps visualize the main subnetting outputs for both IPv4 and IPv6, including split scenarios and more detailed planning workflows.
Because every prefix must start at an address that is a multiple of its own block size; processing the 50-host request first guarantees it occupies a 64-address /26 aligned from the very start of the /24, while starting with small requests would leave gaps too small for the next large request to fit later.
It depends on how close the request lands to the nearest power of 2: requesting 50 hosts costs 12 addresses of slack inside a /26 with 62 usable, while requesting 6 hosts fits with zero slack inside a /29 with exactly 6 usable; the rounder the requested number, the smaller the waste.
Yes: an example with 50, 20, 10 and 6 hosts becomes a /26, /27, /28 and /29 and consumes only 120 of the original /24 256 addresses, leaving 136 free addresses from .120 to .255 for a fifth subnet or future growth without needing another block.
All calculations run locally in your browser. Nothing is sent to the network or to external services.