Linux

IPv4 Subnet Size Reference Chart

Class A

Network BitsSubnet MaskNumber of SubnetsNumber of Hosts
/8255.0.0.0016777214
/9255.128.0.02 (0)8388606
/10255.192.0.04 (2)4194302
/11255.224.0.08 (6)2097150
/12255.240.0.016 (14)1048574
/13255.248.0.032 (30)524286
/14255.252.0.064 (62)262142
/15255.254.0.0128 (126)131070
/16255.255.0.0256 (254)65534
/17255.255.128.0512 (510)32766
/18255.255.192.01024 (1022)16382
/19255.255.224.02048 (2046)8190
/20255.255.240.04096 (4094)4094
/21255.255.248.08192 (8190)2046
/22255.255.252.016384 (16382)1022
/23255.255.254.032768 (32766)510
/24255.255.255.065536 (65534)254
/25255.255.255.128131072 (131070)126
/26255.255.255.192262144 (262142)62
/27255.255.255.224524288 (524286)30
/28255.255.255.2401048576 (1048574)14
/29255.255.255.2482097152 (2097150)6
/30255.255.255.2524194304 (4194302)2

Class B

Network BitsSubnet MaskNumber of SubnetsNumber of Hosts
/16255.255.0.0065534
/17255.255.128.02 (0)32766
/18255.255.192.04 (2)16382
/19255.255.224.08 (6)8190
/20255.255.240.016 (14)4094
/21255.255.248.032 (30)2046
/22255.255.252.064 (62)1022
/23255.255.254.0128 (126)510
/24255.255.255.0256 (254)254
/25255.255.255.128512 (510)126
/26255.255.255.1921024 (1022)62
/27255.255.255.2242048 (2046)30
/28255.255.255.2404096 (4094)14
/29255.255.255.2488192 (8190)6
/30255.255.255.25216384 (16382)2

Class C

Network BitsSubnet MaskNumber of SubnetsNumber of Hosts
/24255.255.255.00254
/25255.255.255.1282 (0)126
/26255.255.255.1924 (2)62
/27255.255.255.2248 (6)30
/28255.255.255.24016 (14)14
/29255.255.255.24832 (30)6
/30255.255.255.25264 (62)2

 


Supernetting (CIDR) Chart

  • CIDR – Classless Inter-Domain Routing.
  • Note: The Number of Class C networks must be contiguous.
    For example, 192.169.1.0/22 represents the following block of addresses:
    192.169.1.0, 192.169.2.0, 192.169.3.0 and 192.169.4.0.

Class C

CIDR BlockSupernet MaskNumber of Class C AddressesNumber of Hosts
/14255.252.0.01024262144
/15255.254.0.0512131072
/16255.255.0.025665536
/17255.255.128.012832768
/18255.255.192.06416384
/19255.255.224.0328192
/20255.255.240.0164096
/21255.255.248.082048
/22255.255.252.041024
/23255.255.254.02512

IPv6 Subnet Size Reference Chart

CIDR SubnetNumber of IP Addresses
/1281
/1272
/1264
/1258
/12416
/12332
/12264
/121128
/120256
/119512
/1181,024
/1172,048
/1164,096
/1158,192
/11416,384
/11332,768
/11265,536
/111131,072
/110262,144
/109524,288
/1081,048,576
/1072,097,152
/1064,194,304
/1058,388,608
/10416,777,216
/10333,554,432
/10267,108,864
/101134,217,728
/100268,435,456
/99536,870,912
/981,073,741,824
/972,147,483,648
/964,294,967,296
/958,589,934,592
/9417,179,869,184
/9334,359,738,368
/9268,719,476,736
/91137,438,953,472
/90274,877,906,944
/89549,755,813,888
/881,099,511,627,776
/872,199,023,255,552
/864,398,046,511,104
/858,796,093,022,208
/8417,592,186,044,416
/8335,184,372,088,832
/8270,368,744,177,664
/81140,737,488,355,328
/80281,474,976,710,656
/79562,949,953,421,312
/781,125,899,906,842,624
/772,251,799,813,685,248
/764,503,599,627,370,496
/759,007,199,254,740,992
/7418,014,398,509,481,985
/7336,028,797,018,963,970
/7272,057,594,037,927,940
/71144,115,188,075,855,870
/70288,230,376,151,711,750
/69576,460,752,303,423,500
/681,152,921,504,606,847,000
/672,305,843,009,213,694,000
/664,611,686,018,427,388,000
/659,223,372,036,854,776,000
Residential: /6418,446,744,073,709,552,000
/6336,893,488,147,419,105,000
/6273,786,976,294,838,210,000
/61147,573,952,589,676,420,000
/60295,147,905,179,352,850,000
/59590,295,810,358,705,700,000
/581,180,591,620,717,411,500,000
/572,361,183,241,434,823,000,000
/564,722,366,482,869,646,000,000
/559,444,732,965,739,292,000,000
/5418,889,465,931,478,585,000,000
/5337,778,931,862,957,170,000,000
/5275,557,863,725,914,340,000,000
/51151,115,727,451,828,670,000,000
/50302,231,454,903,657,430+,000,000
/49604,462,909,807,314,700,000,000
Business: /481,208,925,819,614,629,500,000,000
/472,417,851,639,229,259,000,000,000
/464,835,703,278,458,518,000,000,000
/459,671,406,556,917,036,000,000,000
/4419,342,813,113,834,072,000,000,000
/4338,685,626,227,668,145,000,000,000
/4277,371,252,455,336,290,000,000,000
/41154,742,504,910,672,570,000,000,000
/40309,485,009,821,345,150,000,000,000
/39618,970,019,642,690,200,000,000,000
/381,237,940,039,285,380,500,000,000,000
/372,475,880,078,570,761,000,000,000,000
/364,951,760,157,141,522,000,000,000,000
/359,903,520,314,283,044,000,000,000,000
/3419,807,040,628,566,087,000,000,000,000
/3339,614,081,257,132,168,796,771,975,168
ISP: /3279,228,162,514,264,337,593,543,950,336
/31158,456,325,028,528,675,187,087,900,672
/30316,912,650,057,057,430+,374,175,801,344
/29633,825,300,114,114,700,748,351,602,688
/281,267,650,600,228,229,401,496,703,205,376
/272,535,301,200,456,458,802,993,406,410,752
/265,070,602,400,912,917,605,986,812,821,504
/2510,141,204,801,825,835,211,973,625,643,008
/2420,282,409,603,651,670,423,947,251,286,016
/2340,564,819,207,303,340,847,894,502,572,032
/2281,129,638,414,606,681,695,789,005,144,064
/21162,259,276,829,213,363,391,578,010,288,128
/20324,518,553,658,426,726,783,156,020,576,256
/19649,037,107,316,853,453,566,312,041,152,512
/181,298,074,214,633,706,907,132,624,082,305,024
/172,596,148,429,267,413,814,265,248,164,610,048
/165,192,296,858,534,827,628,530,496,329,220,096
/1510,384,593,717,069,655,257,060,992,658,440,192
/1420,769,187,434,139,310,514,121,985,316,880,384
/1341,538,374,868,278,621,028,243,970,633,760,768
/1283,076,749,736,557,242,056,487,941,267,521,536
/11166,153,499,473,114,484,112,975,882,535,043,072
/10332,306,998,946,228,968,225,951,765,070,086,144
/9664,613,997,892,457,936,451,903,530,140,172,288
/81,329,227,995,784,915,872,903,807,060,280,344,576