CIDR and Netmasks

IPv4
CIDRNetmaskAddressesNotes
/32255.255.255.2551Single address
/31255.255.255.2542
/30255.255.255.2524
/29255.255.255.2488
/28255.255.255.24016
/27255.255.255.22432
/26255.255.255.19264
/25255.255.255.128128
/24255.255.255.0256Class C
/23255.255.254.0512
/22255.255.252.01,024
/21255.255.248.02,048
/20255.255.240.04,096
/19255.255.224.08,192
/18255.255.192.016,384
/17255.255.128.032,768
/16255.255.0.065,536Class B
/15255.254.0.0131,072
/14255.252.0.0262,144
/13255.248.0.0524,288
/12255.240.0.01,048,576
/11255.224.0.02,097,152
/10255.192.0.04,194,304
/9255.128.0.08,388,608
/8255.0.0.016,777,216Class A
/7254.0.0.033,554,432
/6252.0.0.067,108,864
/5248.0.0.0134,217,728
/4240.0.0.0268,435,456
/3224.0.0.0536,870,912
/2192.0.0.01,073,741,824
/1128.0.0.02,147,483,648
/00.0.0.04,294,967,296Entire IPv4 Space
IPv6
CIDRNetmaskAddressesNotes
/128ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff1Single address
/127ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffe2
/126ffff:ffff:ffff:ffff:ffff:ffff:ffff:fffc4
/125ffff:ffff:ffff:ffff:ffff:ffff:ffff:fff88
/124ffff:ffff:ffff:ffff:ffff:ffff:ffff:fff016
/123ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffe032
/122ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffc064
/121ffff:ffff:ffff:ffff:ffff:ffff:ffff:ff80128
/120ffff:ffff:ffff:ffff:ffff:ffff:ffff:ff00256
/119ffff:ffff:ffff:ffff:ffff:ffff:ffff:fe00512
/118ffff:ffff:ffff:ffff:ffff:ffff:ffff:fc001,024
/117ffff:ffff:ffff:ffff:ffff:ffff:ffff:f8002,048
/116ffff:ffff:ffff:ffff:ffff:ffff:ffff:f0004,096
/115ffff:ffff:ffff:ffff:ffff:ffff:ffff:e0008,192
/114ffff:ffff:ffff:ffff:ffff:ffff:ffff:c00016,384
/113ffff:ffff:ffff:ffff:ffff:ffff:ffff:800032,768
/112ffff:ffff:ffff:ffff:ffff:ffff:ffff:065,536
/111ffff:ffff:ffff:ffff:ffff:ffff:fffe:0131,072
/110ffff:ffff:ffff:ffff:ffff:ffff:fffc:0262,144
/109ffff:ffff:ffff:ffff:ffff:ffff:fff8:0524,288
/108ffff:ffff:ffff:ffff:ffff:ffff:fff0:01,048,576
/107ffff:ffff:ffff:ffff:ffff:ffff:ffe0:02,097,152
/106ffff:ffff:ffff:ffff:ffff:ffff:ffc0:04,194,304
/105ffff:ffff:ffff:ffff:ffff:ffff:ff80:08,388,608
/104ffff:ffff:ffff:ffff:ffff:ffff:ff00:016,777,216
/103ffff:ffff:ffff:ffff:ffff:ffff:fe00:033,554,432
/102ffff:ffff:ffff:ffff:ffff:ffff:fc00:067,108,864
/101ffff:ffff:ffff:ffff:ffff:ffff:f800:0134,217,728
/100ffff:ffff:ffff:ffff:ffff:ffff:f000:0268,435,456
/99ffff:ffff:ffff:ffff:ffff:ffff:e000:0536,870,912
/98ffff:ffff:ffff:ffff:ffff:ffff:c000:01,073,741,824
/97ffff:ffff:ffff:ffff:ffff:ffff:8000:02,147,483,648
/96ffff:ffff:ffff:ffff:ffff:ffff::4,294,967,296
/95ffff:ffff:ffff:ffff:ffff:fffe::8,589,934,592
/94ffff:ffff:ffff:ffff:ffff:fffc::17,179,869,184
/93ffff:ffff:ffff:ffff:ffff:fff8::34,359,738,368
/92ffff:ffff:ffff:ffff:ffff:fff0::68,719,476,736
/91ffff:ffff:ffff:ffff:ffff:ffe0::137,438,953,472
/90ffff:ffff:ffff:ffff:ffff:ffc0::274,877,906,944
/89ffff:ffff:ffff:ffff:ffff:ff80::549,755,813,888
/88ffff:ffff:ffff:ffff:ffff:ff00::1,099,511,627,776
/87ffff:ffff:ffff:ffff:ffff:fe00::2,199,023,255,552
/86ffff:ffff:ffff:ffff:ffff:fc00::4,398,046,511,104
/85ffff:ffff:ffff:ffff:ffff:f800::8,796,093,022,208
/84ffff:ffff:ffff:ffff:ffff:f000::17,592,186,044,416
/83ffff:ffff:ffff:ffff:ffff:e000::35,184,372,088,832
/82ffff:ffff:ffff:ffff:ffff:c000::70,368,744,177,664
/81ffff:ffff:ffff:ffff:ffff:8000::140,737,488,355,328
/80ffff:ffff:ffff:ffff:ffff::281,474,976,710,656
/79ffff:ffff:ffff:ffff:fffe::562,949,953,421,312
/78ffff:ffff:ffff:ffff:fffc::1,125,899,906,842,624
/77ffff:ffff:ffff:ffff:fff8::2,251,799,813,685,248
/76ffff:ffff:ffff:ffff:fff0::4,503,599,627,370,496
/75ffff:ffff:ffff:ffff:ffe0::9,007,199,254,740,992
/74ffff:ffff:ffff:ffff:ffc0::18,014,398,509,481,984
/73ffff:ffff:ffff:ffff:ff80::36,028,797,018,963,968
/72ffff:ffff:ffff:ffff:ff00::72,057,594,037,927,936
/71ffff:ffff:ffff:ffff:fe00::144,115,188,075,855,872
/70ffff:ffff:ffff:ffff:fc00::288,230,376,151,711,744
/69ffff:ffff:ffff:ffff:f800::576,460,752,303,423,488
/68ffff:ffff:ffff:ffff:f000::1,152,921,504,606,846,976
/67ffff:ffff:ffff:ffff:e000::2,305,843,009,213,693,952
/66ffff:ffff:ffff:ffff:c000::4,611,686,018,427,387,904
/65ffff:ffff:ffff:ffff:8000::9,223,372,036,854,775,808
/64ffff:ffff:ffff:ffff::1.84467440737096e+19
/63ffff:ffff:ffff:fffe::3.68934881474191e+19
/62ffff:ffff:ffff:fffc::7.37869762948382e+19
/61ffff:ffff:ffff:fff8::1.47573952589676e+20
/60ffff:ffff:ffff:fff0::2.95147905179353e+20
/59ffff:ffff:ffff:ffe0::5.90295810358706e+20
/58ffff:ffff:ffff:ffc0::1.18059162071741e+21
/57ffff:ffff:ffff:ff80::2.36118324143482e+21
/56ffff:ffff:ffff:ff00::4.72236648286965e+21
/55ffff:ffff:ffff:fe00::9.44473296573929e+21
/54ffff:ffff:ffff:fc00::1.88894659314786e+22
/53ffff:ffff:ffff:f800::3.77789318629572e+22
/52ffff:ffff:ffff:f000::7.55578637259143e+22
/51ffff:ffff:ffff:e000::1.51115727451829e+23
/50ffff:ffff:ffff:c000::3.02231454903657e+23
/49ffff:ffff:ffff:8000::6.04462909807315e+23
/48ffff:ffff:ffff::1.20892581961463e+24
/47ffff:ffff:fffe::2.41785163922926e+24
/46ffff:ffff:fffc::4.83570327845852e+24
/45ffff:ffff:fff8::9.67140655691703e+24
/44ffff:ffff:fff0::1.93428131138341e+25
/43ffff:ffff:ffe0::3.86856262276681e+25
/42ffff:ffff:ffc0::7.73712524553363e+25
/41ffff:ffff:ff80::1.54742504910673e+26
/40ffff:ffff:ff00::3.09485009821345e+26
/39ffff:ffff:fe00::6.1897001964269e+26
/38ffff:ffff:fc00::1.23794003928538e+27
/37ffff:ffff:f800::2.47588007857076e+27
/36ffff:ffff:f000::4.95176015714152e+27
/35ffff:ffff:e000::9.90352031428304e+27
/34ffff:ffff:c000::1.98070406285661e+28
/33ffff:ffff:8000::3.96140812571322e+28
/32ffff:ffff::7.92281625142643e+28Equivalent to 1 IPv4 address
/31ffff:fffe::1.58456325028529e+29
/30ffff:fffc::3.16912650057057e+29
/29ffff:fff8::6.33825300114115e+29
/28ffff:fff0::1.26765060022823e+30
/27ffff:ffe0::2.53530120045646e+30
/26ffff:ffc0::5.07060240091292e+30
/25ffff:ff80::1.01412048018258e+31
/24ffff:ff00::2.02824096036517e+31
/23ffff:fe00::4.05648192073033e+31
/22ffff:fc00::8.11296384146067e+31
/21ffff:f800::1.62259276829213e+32
/20ffff:f000::3.24518553658427e+32
/19ffff:e000::6.49037107316853e+32
/18ffff:c000::1.29807421463371e+33
/17ffff:8000::2.59614842926741e+33
/16ffff::5.19229685853483e+33
/15fffe::1.03845937170697e+34
/14fffc::2.07691874341393e+34
/13fff8::4.15383748682786e+34
/12fff0::8.30767497365572e+34
/11ffe0::1.66153499473114e+35
/10ffc0::3.32306998946229e+35
/9ff80::6.64613997892458e+35
/8ff00::1.32922799578492e+36
/7fe00::2.65845599156983e+36
/6fc00::5.31691198313966e+36
/5f800::1.06338239662793e+37
/4f000::2.12676479325587e+37
/3e000::4.25352958651173e+37
/2c000::8.50705917302346e+37
/18000::1.70141183460469e+38
/0::3.40282366920938e+38Entire IPv6 Space