Know your subnet.
Plan the address range.
Enter an IPv4 address and prefix. See its containing network, mask and conventional host range.
Address profile
01 / INPUTSSubnet details
02 / RESULTSTotal addresses in block
Address plan
A range is arithmetic.
Availability is operational.
Address counts do not establish that addresses can be assigned, routed or reached.
Conventional host counts
For /0–/30, the displayed host range excludes the block’s first and last addresses. Special-use ranges, cloud reservations, gateways, DHCP exclusions and existing allocations can reduce assignable addresses. A /0 describes all IPv4 addresses; it is not a practical host subnet.
/31 point-to-point links
Both addresses are endpoints under RFC 3021 when used on a supported point-to-point link. There is no subnet-directed broadcast in this interpretation. Verify both devices support /31.
/32 single-address blocks
A /32 identifies one address, commonly a host route or loopback. The one-address count does not imply a conventional LAN subnet or guarantee assignability.
IPv4 only. This calculator does not apply cloud-specific address reservations.