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Subnet /30: Mask 255.255.255.252, 2 Hosts for P2P Links

Calculate the network address, broadcast, subnet and wildcard masks, host range and usable host count for any IPv4 address and CIDR prefix.

Processing... 0%
Parsing IPv4 address
Applying subnet mask
Computing host range
Done

Result

A /30 prefix keeps 30 of the 32 IPv4 bits for the network and leaves only 2 bits for hosts — the smallest classic subnet that still has usable addresses. Network engineers reach for it constantly: a point-to-point link between two routers needs exactly two addresses, one per interface, and a /30 provides precisely that with no waste beyond the two reserved addresses.

The subnet mask is 255.255.255.252. Two host bits give 2^2 = 4 addresses, and after the network and broadcast addresses are set aside 2^2 − 2 = 2 usable hosts remain. In 10.0.0.4/30, for example, the network address is 10.0.0.4, the two usable hosts are 10.0.0.5 and 10.0.0.6, and 10.0.0.7 is the broadcast. Modern gear can squeeze links into /31 (RFC 3021), but /30 remains the safe, universally supported choice.

This page opens the subnet calculator with /30 preselected: enter any IPv4 address and it aligns it to the enclosing /30 block, showing the network, broadcast, wildcard mask 0.0.0.3 and both usable hosts. Everything is computed with 32-bit integer math right in your browser — private, instant and available offline once the page has loaded.

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Executed in Browser

Your files and inputs never leave this device. Processing runs completely offline. 100% Secure.

Accepted Formats & Rules

  • Network address, broadcast address, subnet mask and wildcard mask for any IPv4/CIDR pair.
  • First and last usable host plus usable-host and total-address counts (2^(32−p) − 2 arithmetic).
  • IP class note for the entered address and a one-click copy of the full result summary.

Key Benefits

✓ One input pair — IP address and prefix — returns everything at once: network, broadcast, both masks, host range and address counts.
✓ Pure 32-bit integer math computed locally in your browser: no server round-trip, no lookup tables, correct for every prefix from /8 to /30.
✓ The IP class note explains what the first octet implies — classful history, loopback and reserved ranges — so the numbers come with context.

Use Cases

  • • Size a VLAN or office LAN: check how many usable hosts a /23 or /24 really gives before assigning the range.
  • • Fill in firewall or ACL rules with the exact network address, wildcard mask and broadcast for any IP/prefix pair.
  • • Practice CIDR arithmetic for networking exams by verifying your hand-calculated masks, ranges and host counts.