Free Tool

IP Subnet Calculator

Instantly calculate network address, broadcast, host range and more for any IPv4 subnet.

Subnets

#	CIDR	Network	First Host	Last Host	Last Address

What is an IP subnet calculator?

An IP subnet calculator takes an IPv4 or IPv6 address and a subnet mask (or CIDR prefix) and instantly returns the network address, broadcast address, usable host range, total and usable host count, wildcard mask, and IP class. It saves you from doing binary math by hand when planning or troubleshooting a network.

How to use this tool

Choose IPv4 or IPv6.
Enter any IP address (for example 192.168.1.10 or
2001:db8::).
Enter a CIDR prefix like /24 or a dotted netmask like
255.255.255.0.
Optionally split the network into 2, 4, 8 or more equal subnets.
Results update instantly as you
type.

Understanding CIDR notation

CIDR (Classless Inter-Domain Routing) notation expresses a subnet mask as the number of leading 1-bits. /24 means the first 24 bits identify the network and the remaining 8 bits identify hosts — equivalent to 255.255.255.0 and 254 usable hosts per subnet.

Common CIDR blocks

CIDR	Subnet Mask	Wildcard	Total Addresses	Usable Hosts
/30	255.255.255.252	0.0.0.3	4	2
/29	255.255.255.248	0.0.0.7	8	6
/28	255.255.255.240	0.0.0.15	16	14
/27	255.255.255.224	0.0.0.31	32	30
/26	255.255.255.192	0.0 .0.63	64	62
/25	255.255.255.128	0.0.0.127	128	126
/24	255.255.255.0	0.0.0.255	256	254
/23	255.255.254.0	0.0.1.255	512	510
/22	255.255.252.0	0.0.3.255	1,024	1,022
/21	255.255.248.0	0.0.7.2 55	2,048	2,046
/20	255.255.240.0	0.0.15.255	4,096	4,094
/19	255.255.224.0	0.0.31.255	8,192	8,190
/18	255.255.192.0	0.0.63.255	16,384< /td>	16,382
/17	255.255.128.0	0.0.127.255	32,768	32,766
/16	255.255 .0.0	0.0.255.255	65,536	65,534
/8	255.0.0.0	0.255.255.255	16,777,216	16 ,777,214

Privacy

This calculator runs entirely in your browser. No IP addresses or queries are sent to our servers.