IPv4 Subnet Calculator

This calculator and tool allows you to type an IP address in and get information on a particular subnet. Enter an IP or range in CIDR notation.

Network: 4.0.28.66/31
Addresses: 2 (2¹)
First IP: 4.0.28.66 (66.28.0.4.in-addr.arpa)
Last IP: 4.0.28.67 (67.28.0.4.in-addr.arpa)

Owned By: Level 3
/8 Operated By: ARIN

Related Networks

4.0.0.0/8
3.0.0.0/8
5.0.0.0/8
4.0.28.64/30
4.0.28.66/32
4.0.28.67/32

You can also use some of the other examples such as:

0.0.0.0/0
1.0.0.0/8
127.0.0.1
30.0.0.0/8
192.168.0.0/16