Arsenal / Free tool
Subnet Calculator
Type an address and a prefix. See the network, broadcast, host range and every bit that decides them. Then plan subnets and drill the math until it is automatic.
01 / Input
Address and prefix
Everything is calculated in your browser. Nothing you type leaves this page.
02 / Result
Subnet details
Binary view
Green = network bitsYellow = host bits
How it works (block-size method)
Subnet planner
Carve up a network
Give the planner the block you were assigned. Size each subnet by the hosts it needs (VLSM), or split it into equal pieces.
Practice mode
Solve it, then check the working
Score 0 / 0 Streak 0
Questions cover network IDs, broadcasts, host ranges, host counts, masks and wildcards. Scratch paper is encouraged: the exam gives you a whiteboard.
IPv6 basics
Expand and compress
Compression rules
- Drop leading zeros in each group:
0db8becomesdb8. - Replace one run of all-zero groups with
::, the longest run (leftmost if tied). ::can appear only once, or the address becomes ambiguous.- Most LANs use a /64: the first 4 groups are the network, the last 4 are the interface ID.
Result