IPv4 CIDR

Prefix	Subnet Mask	Wildcard Mask	Addresses	Size	Usable Hosts	Typical Usage
/32	255.255.255.255	0.0.0.0	1	2^0	1	Host
/31	255.255.255.254	0.0.0.1	2	2^1	0	Point to Point (RFC 3012)
/30	255.255.255.252	0.0.0.3	4	2^2	2	Point to Point
/29	255.255.255.248	0.0.0.7	8	2^3	6	Small WAN Block
/28	255.255.255.240	0.0.0.15	16	2^4	14
/27	255.255.255.224	0.0.0.31	32	2^5	30
/26	255.255.255.192	0.0.0.63	64	2^6	62
/25	255.255.255.128	0.0.0.127	128	2^7	126
/24	255.255.255.0	0.0.0.255	256	2^8	254
/23	255.255.254.0	0.0.1.255	512	2^9	510
/22	255.255.252.0	0.0.3.255	1,024	2^10	1,022
/21	255.255.248.0	0.0.7.255	2,048	2^11	2,046
/20	255.255.240.0	0.0.15.255	4,096	2^12	4,094
/19	255.255.224.0	0.0.31.255	8,192	2^13	8,190
/18	255.255.192.0	0.0.63.255	16,384	2^14	16,382
/17	255.255.128.0	0.0.127.255	32,768	2^15	32,766
/16	255.255.0.0	0.0.255.255	65,536	2^16	65,534
/15	255.254.0.0	0.1.255.255	131,072	2^17	131,070
/14	255.252.0.0	0.3.255.255	262,144	2^18	262,142
/13	255.248.0.0	0.7.255.255	524,288	2^19	524,286
/12	255.240.0.0	0.15.255.255	1,048,576	2^20	1,048,574
/11	255.224.0.0	0.31.255.255	2,097,152	2^21	2,097,150
/10	255.192.0.0	0.63.255.255	4,194,304	2^22	4,194,302
/9	255.128.0.0	0.127.255.255	8,388,608	2^23	8,388,606
/8	255.0.0.0	0.255.255.255	16,777,216	2^24	16,777,212
/7	254.0.0.0	1.255.255.255	33,554,432	2^25	33,554,430
/6	252.0.0.0	3.255.255.255	67,108,864	2^26	67,108,862
/5	248.0.0.0	7.255.255.255	134,217,728	2^27	134,217,726
/4	240.0.0.0	15.255.255.255	268,435,456	2^28	268,435,454
/3	224.0.0.0	31.255.255.255	536,870,912	2^29	536,870,910
/2	192.0.0.0	63.255.255.255	1,073,741,824	2^30	1,073,741,822
/1	128.0.0.0	127.255.255.255	2,147,483,648	2^31	2,147,483,646
/0	0.0.0.0	255.255.255.255	4,294,967,296	2^32	4,294,967,294	IPv4 Internet