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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network80.0.0.0/4
Usable hosts268,435,454
Subnet mask240.0.0.0
Addresses268,435,456
Network address
80.0.0.0
Broadcast address
95.255.255.255
First usable
80.0.0.1
Last usable
95.255.255.254
Usable hosts
268,435,454 (268,435,456 less the network and broadcast addresses)
Subnet mask
240.0.0.0
Wildcard mask
15.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/4
Type
Public public
Old class
A (default /8)
As numbers
Hex 50000000 · Integer 1342177280 to 1610612735
Reverse DNS zones
80.in-addr.arpa
81.in-addr.arpa
82.in-addr.arpa
83.in-addr.arpa
84.in-addr.arpa
85.in-addr.arpa
86.in-addr.arpa
87.in-addr.arpa
88.in-addr.arpa
89.in-addr.arpa
90.in-addr.arpa
91.in-addr.arpa
92.in-addr.arpa
93.in-addr.arpa
94.in-addr.arpa
95.in-addr.arpa
/4 is not on a 8-bit boundary, so it takes 16 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01010000.00000000.00000000.0000000080.0.0.0
Subnet mask11110000.00000000.00000000.00000000240.0.0.0
Network01010000.00000000.00000000.0000000080.0.0.0
Broadcast01011111.11111111.11111111.1111111195.255.255.255
Split into smaller subnets/11
/5 (2)/6 (4)/7 (8)/8 (16)/9 (32)/10 (64)/11 (128)/12 (256)/13 (512)/14 (1,024)/15 (2,048)/16 (4,096)

80.0.0.0/4 makes 128 subnets of /11.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
180.0.0.0/1180.0.0.1 to 80.31.255.25480.31.255.2552,097,150
280.32.0.0/1180.32.0.1 to 80.63.255.25480.63.255.2552,097,150
380.64.0.0/1180.64.0.1 to 80.95.255.25480.95.255.2552,097,150
480.96.0.0/1180.96.0.1 to 80.127.255.25480.127.255.2552,097,150
580.128.0.0/1180.128.0.1 to 80.159.255.25480.159.255.2552,097,150
680.160.0.0/1180.160.0.1 to 80.191.255.25480.191.255.2552,097,150
780.192.0.0/1180.192.0.1 to 80.223.255.25480.223.255.2552,097,150
880.224.0.0/1180.224.0.1 to 80.255.255.25480.255.255.2552,097,150
981.0.0.0/1181.0.0.1 to 81.31.255.25481.31.255.2552,097,150
1081.32.0.0/1181.32.0.1 to 81.63.255.25481.63.255.2552,097,150
1181.64.0.0/1181.64.0.1 to 81.95.255.25481.95.255.2552,097,150
1281.96.0.0/1181.96.0.1 to 81.127.255.25481.127.255.2552,097,150
1381.128.0.0/1181.128.0.1 to 81.159.255.25481.159.255.2552,097,150
1481.160.0.0/1181.160.0.1 to 81.191.255.25481.191.255.2552,097,150
1581.192.0.0/1181.192.0.1 to 81.223.255.25481.223.255.2552,097,150
1681.224.0.0/1181.224.0.1 to 81.255.255.25481.255.255.2552,097,150
1782.0.0.0/1182.0.0.1 to 82.31.255.25482.31.255.2552,097,150
1882.32.0.0/1182.32.0.1 to 82.63.255.25482.63.255.2552,097,150
1982.64.0.0/1182.64.0.1 to 82.95.255.25482.95.255.2552,097,150
2082.96.0.0/1182.96.0.1 to 82.127.255.25482.127.255.2552,097,150
2182.128.0.0/1182.128.0.1 to 82.159.255.25482.159.255.2552,097,150
2282.160.0.0/1182.160.0.1 to 82.191.255.25482.191.255.2552,097,150
2382.192.0.0/1182.192.0.1 to 82.223.255.25482.223.255.2552,097,150
2482.224.0.0/1182.224.0.1 to 82.255.255.25482.255.255.2552,097,150
2583.0.0.0/1183.0.0.1 to 83.31.255.25483.31.255.2552,097,150
2683.32.0.0/1183.32.0.1 to 83.63.255.25483.63.255.2552,097,150
2783.64.0.0/1183.64.0.1 to 83.95.255.25483.95.255.2552,097,150
2883.96.0.0/1183.96.0.1 to 83.127.255.25483.127.255.2552,097,150
2983.128.0.0/1183.128.0.1 to 83.159.255.25483.159.255.2552,097,150
3083.160.0.0/1183.160.0.1 to 83.191.255.25483.191.255.2552,097,150
3183.192.0.0/1183.192.0.1 to 83.223.255.25483.223.255.2552,097,150
3283.224.0.0/1183.224.0.1 to 83.255.255.25483.255.255.2552,097,150
3384.0.0.0/1184.0.0.1 to 84.31.255.25484.31.255.2552,097,150
3484.32.0.0/1184.32.0.1 to 84.63.255.25484.63.255.2552,097,150
3584.64.0.0/1184.64.0.1 to 84.95.255.25484.95.255.2552,097,150
3684.96.0.0/1184.96.0.1 to 84.127.255.25484.127.255.2552,097,150
3784.128.0.0/1184.128.0.1 to 84.159.255.25484.159.255.2552,097,150
3884.160.0.0/1184.160.0.1 to 84.191.255.25484.191.255.2552,097,150
3984.192.0.0/1184.192.0.1 to 84.223.255.25484.223.255.2552,097,150
4084.224.0.0/1184.224.0.1 to 84.255.255.25484.255.255.2552,097,150
4185.0.0.0/1185.0.0.1 to 85.31.255.25485.31.255.2552,097,150
4285.32.0.0/1185.32.0.1 to 85.63.255.25485.63.255.2552,097,150
4385.64.0.0/1185.64.0.1 to 85.95.255.25485.95.255.2552,097,150
4485.96.0.0/1185.96.0.1 to 85.127.255.25485.127.255.2552,097,150
4585.128.0.0/1185.128.0.1 to 85.159.255.25485.159.255.2552,097,150
4685.160.0.0/1185.160.0.1 to 85.191.255.25485.191.255.2552,097,150
4785.192.0.0/1185.192.0.1 to 85.223.255.25485.223.255.2552,097,150
4885.224.0.0/1185.224.0.1 to 85.255.255.25485.255.255.2552,097,150
4986.0.0.0/1186.0.0.1 to 86.31.255.25486.31.255.2552,097,150
5086.32.0.0/1186.32.0.1 to 86.63.255.25486.63.255.2552,097,150
5186.64.0.0/1186.64.0.1 to 86.95.255.25486.95.255.2552,097,150
5286.96.0.0/1186.96.0.1 to 86.127.255.25486.127.255.2552,097,150
5386.128.0.0/1186.128.0.1 to 86.159.255.25486.159.255.2552,097,150
5486.160.0.0/1186.160.0.1 to 86.191.255.25486.191.255.2552,097,150
5586.192.0.0/1186.192.0.1 to 86.223.255.25486.223.255.2552,097,150
5686.224.0.0/1186.224.0.1 to 86.255.255.25486.255.255.2552,097,150
5787.0.0.0/1187.0.0.1 to 87.31.255.25487.31.255.2552,097,150
5887.32.0.0/1187.32.0.1 to 87.63.255.25487.63.255.2552,097,150
5987.64.0.0/1187.64.0.1 to 87.95.255.25487.95.255.2552,097,150
6087.96.0.0/1187.96.0.1 to 87.127.255.25487.127.255.2552,097,150
6187.128.0.0/1187.128.0.1 to 87.159.255.25487.159.255.2552,097,150
6287.160.0.0/1187.160.0.1 to 87.191.255.25487.191.255.2552,097,150
6387.192.0.0/1187.192.0.1 to 87.223.255.25487.223.255.2552,097,150
6487.224.0.0/1187.224.0.1 to 87.255.255.25487.255.255.2552,097,150
6588.0.0.0/1188.0.0.1 to 88.31.255.25488.31.255.2552,097,150
6688.32.0.0/1188.32.0.1 to 88.63.255.25488.63.255.2552,097,150
6788.64.0.0/1188.64.0.1 to 88.95.255.25488.95.255.2552,097,150
6888.96.0.0/1188.96.0.1 to 88.127.255.25488.127.255.2552,097,150
6988.128.0.0/1188.128.0.1 to 88.159.255.25488.159.255.2552,097,150
7088.160.0.0/1188.160.0.1 to 88.191.255.25488.191.255.2552,097,150
7188.192.0.0/1188.192.0.1 to 88.223.255.25488.223.255.2552,097,150
7288.224.0.0/1188.224.0.1 to 88.255.255.25488.255.255.2552,097,150
7389.0.0.0/1189.0.0.1 to 89.31.255.25489.31.255.2552,097,150
7489.32.0.0/1189.32.0.1 to 89.63.255.25489.63.255.2552,097,150
7589.64.0.0/1189.64.0.1 to 89.95.255.25489.95.255.2552,097,150
7689.96.0.0/1189.96.0.1 to 89.127.255.25489.127.255.2552,097,150
7789.128.0.0/1189.128.0.1 to 89.159.255.25489.159.255.2552,097,150
7889.160.0.0/1189.160.0.1 to 89.191.255.25489.191.255.2552,097,150
7989.192.0.0/1189.192.0.1 to 89.223.255.25489.223.255.2552,097,150
8089.224.0.0/1189.224.0.1 to 89.255.255.25489.255.255.2552,097,150
8190.0.0.0/1190.0.0.1 to 90.31.255.25490.31.255.2552,097,150
8290.32.0.0/1190.32.0.1 to 90.63.255.25490.63.255.2552,097,150
8390.64.0.0/1190.64.0.1 to 90.95.255.25490.95.255.2552,097,150
8490.96.0.0/1190.96.0.1 to 90.127.255.25490.127.255.2552,097,150
8590.128.0.0/1190.128.0.1 to 90.159.255.25490.159.255.2552,097,150
8690.160.0.0/1190.160.0.1 to 90.191.255.25490.191.255.2552,097,150
8790.192.0.0/1190.192.0.1 to 90.223.255.25490.223.255.2552,097,150
8890.224.0.0/1190.224.0.1 to 90.255.255.25490.255.255.2552,097,150
8991.0.0.0/1191.0.0.1 to 91.31.255.25491.31.255.2552,097,150
9091.32.0.0/1191.32.0.1 to 91.63.255.25491.63.255.2552,097,150
9191.64.0.0/1191.64.0.1 to 91.95.255.25491.95.255.2552,097,150
9291.96.0.0/1191.96.0.1 to 91.127.255.25491.127.255.2552,097,150
9391.128.0.0/1191.128.0.1 to 91.159.255.25491.159.255.2552,097,150
9491.160.0.0/1191.160.0.1 to 91.191.255.25491.191.255.2552,097,150
9591.192.0.0/1191.192.0.1 to 91.223.255.25491.223.255.2552,097,150
9691.224.0.0/1191.224.0.1 to 91.255.255.25491.255.255.2552,097,150
9792.0.0.0/1192.0.0.1 to 92.31.255.25492.31.255.2552,097,150
9892.32.0.0/1192.32.0.1 to 92.63.255.25492.63.255.2552,097,150
9992.64.0.0/1192.64.0.1 to 92.95.255.25492.95.255.2552,097,150
10092.96.0.0/1192.96.0.1 to 92.127.255.25492.127.255.2552,097,150
10192.128.0.0/1192.128.0.1 to 92.159.255.25492.159.255.2552,097,150
10292.160.0.0/1192.160.0.1 to 92.191.255.25492.191.255.2552,097,150
10392.192.0.0/1192.192.0.1 to 92.223.255.25492.223.255.2552,097,150
10492.224.0.0/1192.224.0.1 to 92.255.255.25492.255.255.2552,097,150
10593.0.0.0/1193.0.0.1 to 93.31.255.25493.31.255.2552,097,150
10693.32.0.0/1193.32.0.1 to 93.63.255.25493.63.255.2552,097,150
10793.64.0.0/1193.64.0.1 to 93.95.255.25493.95.255.2552,097,150
10893.96.0.0/1193.96.0.1 to 93.127.255.25493.127.255.2552,097,150
10993.128.0.0/1193.128.0.1 to 93.159.255.25493.159.255.2552,097,150
11093.160.0.0/1193.160.0.1 to 93.191.255.25493.191.255.2552,097,150
11193.192.0.0/1193.192.0.1 to 93.223.255.25493.223.255.2552,097,150
11293.224.0.0/1193.224.0.1 to 93.255.255.25493.255.255.2552,097,150
11394.0.0.0/1194.0.0.1 to 94.31.255.25494.31.255.2552,097,150
11494.32.0.0/1194.32.0.1 to 94.63.255.25494.63.255.2552,097,150
11594.64.0.0/1194.64.0.1 to 94.95.255.25494.95.255.2552,097,150
11694.96.0.0/1194.96.0.1 to 94.127.255.25494.127.255.2552,097,150
11794.128.0.0/1194.128.0.1 to 94.159.255.25494.159.255.2552,097,150
11894.160.0.0/1194.160.0.1 to 94.191.255.25494.191.255.2552,097,150
11994.192.0.0/1194.192.0.1 to 94.223.255.25494.223.255.2552,097,150
12094.224.0.0/1194.224.0.1 to 94.255.255.25494.255.255.2552,097,150
12195.0.0.0/1195.0.0.1 to 95.31.255.25495.31.255.2552,097,150
12295.32.0.0/1195.32.0.1 to 95.63.255.25495.63.255.2552,097,150
12395.64.0.0/1195.64.0.1 to 95.95.255.25495.95.255.2552,097,150
12495.96.0.0/1195.96.0.1 to 95.127.255.25495.127.255.2552,097,150
12595.128.0.0/1195.128.0.1 to 95.159.255.25495.159.255.2552,097,150
12695.160.0.0/1195.160.0.1 to 95.191.255.25495.191.255.2552,097,150
12795.192.0.0/1195.192.0.1 to 95.223.255.25495.223.255.2552,097,150
12895.224.0.0/1195.224.0.1 to 95.255.255.25495.255.255.2552,097,150

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.