A fuller printable subnetting pack covering CIDR, subnet masks, wildcard masks, host counts, and network boundaries with binary-first explanations and quick lookup logic.
Use this pack when you need subnetting logic in front of you: CIDR boundaries, dotted-decimal masks, host counts, wildcard masks, and worked network-range examples.
CIDR and subnet masks are the same boundary expressed differently. The key step is identifying how many host bits remain and which octet contains the changing block size.
A /27 gives 32 total addresses and 30 usable hosts. In the final octet the block size is 32, so ranges start at .0, .32, .64, and so on.
Around 50 usable hosts needs a /26 rather than a /27. Design is often easier when you start from host requirement and only then choose the smallest prefix with headroom.
Wildcard masks are useful for ACL-style matching and should be mentally separated from routed subnet boundaries even though they are directly related mathematically.
Work out the network address, broadcast address, host range, and mask details for an IPv4 network from the address and prefix you enter.
Use the CIDR from Subnet Mask Calculator to work out cidr from subnet mask for networking, storage, or systems planning.
Use the Subnet Mask from CIDR Calculator to work out subnet mask from cidr for networking, storage, or systems planning.
Use the Wildcard Mask from CIDR Calculator to work out wildcard mask from cidr for networking, storage, or systems planning.
Use the Subnet Host Count Calculator to work out subnet host count for networking, storage, or systems planning.