IPv4 CIDR

Prefix	Subnet Mask	Addresses	Size	Usable Hosts	Wildcard Mask	Typical Usage
/32	255.255.255.255	1	2^0	1	0.0.0.0	Host
/31	255.255.255.254	2	2^1	0	0.0.0.1	Point to Point Links
/30	255.255.255.252	4	2^2	2	0.0.0.3	Point to Point Links
/29	255.255.255.248	8	2^3	6	0.0.0.7	Small WAN Block
/28	255.255.255.240	16	2^4	14	0.0.0.15
/27	255.255.255.224	32	2^5	30	0.0.0.31
/26	255.255.255.192	64	2^6	62	0.0.0.63
/25	255.255.255.128	128	2^7	126	0.0.0.127
/24	255.255.255.0	256	2^8	254	0.0.0.255
/23	255.255.254.0	512	2^9	510	0.0.1.255
/22	255.255.252.0	1,024	2^10	1,022	0.0.3.255
/21	255.255.248.0	2,048	2^11	2,046	0.0.7.255
/20	255.255.240.0	4,096	2^12	4,094	0.0.15.255
/19	255.255.224.0	8,192	2^13	8,190	0.0.31.255
/18	255.255.192.0	16,384	2^14	16,382	0.0.63.255
/17	255.255.128.0	32,768	2^15	32,766	0.0.127.255
/16	255.255.0.0	65,536	2^16	65,534	0.0.255.255
/15	255.254.0.0	131,072	2^17	131,070	0.1.255.255
/14	255.252.0.0	262,144	2^18	262,142	0.3.255.255
/13	255.248.0.0	524,288	2^19	524,286	0.7.255.255
/12	255.240.0.0	1,048,576	2^20	1,048,574	0.15.255.255
/11	255.224.0.0	2,097,152	2^21	2,097,150	0.31.255.255
/10	255.192.0.0	4,194,304	2^22	4,194,302	0.63.255.255
/9	255.128.0.0	8,388,608	2^23	8,388,606	0.127.255.255
/8	255.0.0.0	16,777,216	2^24	16,777,212	0.255.255.255
/7	254.0.0.0	33,554,432	2^25	33,554,430	1.255.255.255
/6	252.0.0.0	67,108,864	2^26	67,108,862	3.255.255.255
/5	248.0.0.0	134,217,728	2^27	134,217,726	7.255.255.255
/4	240.0.0.0	268,435,456	2^28	268,435,454	15.255.255.255
/3	224.0.0.0	536,870,912	2^29	536,870,910	31.255.255.255
/2	192.0.0.0	1,073,741,824	2^30	1,073,741,822	63.255.255.255
/1	128.0.0.0	2,147,483,648	2^31	2,147,483,646	127.255.255.255
/0	0.0.0.0	4,294,967,296	2^32	4,294,967,294	255.255.255.255	Default route for IPv4 Internet