Subnet Calculator & CIDR IP Tool

High-precision subnet calculator for IPv4 and IPv6: network range, broadcast or last address, first/last usable hosts, wildcard mask, binary breakdown, and address class. All processing is local.

🔒 Processed 100% in-browser. Network configurations never leave your device.
CIDR prefix length: /240–32

Network address

Broadcast address

Wildcard mask

First usable host

Last usable host

Total usable hosts (IPv4)

254

Subnet mask / prefix

255.255.255.0

Binary view (network vs host)

Network·Host
11000000.
10101000.
00000001.
00001010

IP auditor

Private (RFC 1918)

How to use Subnet Calculator

  1. 1Pick IPv4 or IPv6 and enter an address (you can include a prefix, e.g. 192.168.1.1/24 or 2001:db8::1/64).
  2. 2Adjust the CIDR slider or type an IPv4 dotted-decimal mask (e.g. 255.255.255.0) to derive the prefix.
  3. 3Read network, broadcast (IPv4) or last subnet address (IPv6), first/last usable hosts, total count, and wildcard mask.
  4. 4Inspect the binary view for network vs host bits and the IP auditor for scope (public, private, loopback, and more).

Privacy

Subnet math runs entirely in your browser. IP addresses and masks are never uploaded or stored.

🔒 Processed 100% in-browser. Network configurations never leave your device.