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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.

Network182.0.0.0/11
Usable hosts2,097,150
Subnet mask255.224.0.0
Addresses2,097,152
Network address
182.0.0.0
Broadcast address
182.31.255.255
First usable
182.0.0.1
Last usable
182.31.255.254
Usable hosts
2,097,150 (2,097,152 less the network and broadcast addresses)
Subnet mask
255.224.0.0
Wildcard mask
0.31.255.255 (Cisco ACLs, OSPF)
Prefix length
/11
Type
Public public
Old class
B (default /16)
As numbers
Hex B6000000 · Integer 3053453312 to 3055550463
Reverse DNS zones
0.182.in-addr.arpa
1.182.in-addr.arpa
2.182.in-addr.arpa
3.182.in-addr.arpa
4.182.in-addr.arpa
5.182.in-addr.arpa
6.182.in-addr.arpa
7.182.in-addr.arpa
8.182.in-addr.arpa
9.182.in-addr.arpa
10.182.in-addr.arpa
11.182.in-addr.arpa
12.182.in-addr.arpa
13.182.in-addr.arpa
14.182.in-addr.arpa
15.182.in-addr.arpa
and 16 more
/11 is not on a 8-bit boundary, so it takes 32 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110110.00000000.00000000.00000000182.0.0.0
Subnet mask11111111.11100000.00000000.00000000255.224.0.0
Network10110110.00000000.00000000.00000000182.0.0.0
Broadcast10110110.00011111.11111111.11111111182.31.255.255
Split into smaller subnets/18
/12 (2)/13 (4)/14 (8)/15 (16)/16 (32)/17 (64)/18 (128)/19 (256)/20 (512)/21 (1,024)/22 (2,048)/23 (4,096)

182.0.0.0/11 makes 128 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1182.0.0.0/18182.0.0.1 to 182.0.63.254182.0.63.25516,382
2182.0.64.0/18182.0.64.1 to 182.0.127.254182.0.127.25516,382
3182.0.128.0/18182.0.128.1 to 182.0.191.254182.0.191.25516,382
4182.0.192.0/18182.0.192.1 to 182.0.255.254182.0.255.25516,382
5182.1.0.0/18182.1.0.1 to 182.1.63.254182.1.63.25516,382
6182.1.64.0/18182.1.64.1 to 182.1.127.254182.1.127.25516,382
7182.1.128.0/18182.1.128.1 to 182.1.191.254182.1.191.25516,382
8182.1.192.0/18182.1.192.1 to 182.1.255.254182.1.255.25516,382
9182.2.0.0/18182.2.0.1 to 182.2.63.254182.2.63.25516,382
10182.2.64.0/18182.2.64.1 to 182.2.127.254182.2.127.25516,382
11182.2.128.0/18182.2.128.1 to 182.2.191.254182.2.191.25516,382
12182.2.192.0/18182.2.192.1 to 182.2.255.254182.2.255.25516,382
13182.3.0.0/18182.3.0.1 to 182.3.63.254182.3.63.25516,382
14182.3.64.0/18182.3.64.1 to 182.3.127.254182.3.127.25516,382
15182.3.128.0/18182.3.128.1 to 182.3.191.254182.3.191.25516,382
16182.3.192.0/18182.3.192.1 to 182.3.255.254182.3.255.25516,382
17182.4.0.0/18182.4.0.1 to 182.4.63.254182.4.63.25516,382
18182.4.64.0/18182.4.64.1 to 182.4.127.254182.4.127.25516,382
19182.4.128.0/18182.4.128.1 to 182.4.191.254182.4.191.25516,382
20182.4.192.0/18182.4.192.1 to 182.4.255.254182.4.255.25516,382
21182.5.0.0/18182.5.0.1 to 182.5.63.254182.5.63.25516,382
22182.5.64.0/18182.5.64.1 to 182.5.127.254182.5.127.25516,382
23182.5.128.0/18182.5.128.1 to 182.5.191.254182.5.191.25516,382
24182.5.192.0/18182.5.192.1 to 182.5.255.254182.5.255.25516,382
25182.6.0.0/18182.6.0.1 to 182.6.63.254182.6.63.25516,382
26182.6.64.0/18182.6.64.1 to 182.6.127.254182.6.127.25516,382
27182.6.128.0/18182.6.128.1 to 182.6.191.254182.6.191.25516,382
28182.6.192.0/18182.6.192.1 to 182.6.255.254182.6.255.25516,382
29182.7.0.0/18182.7.0.1 to 182.7.63.254182.7.63.25516,382
30182.7.64.0/18182.7.64.1 to 182.7.127.254182.7.127.25516,382
31182.7.128.0/18182.7.128.1 to 182.7.191.254182.7.191.25516,382
32182.7.192.0/18182.7.192.1 to 182.7.255.254182.7.255.25516,382
33182.8.0.0/18182.8.0.1 to 182.8.63.254182.8.63.25516,382
34182.8.64.0/18182.8.64.1 to 182.8.127.254182.8.127.25516,382
35182.8.128.0/18182.8.128.1 to 182.8.191.254182.8.191.25516,382
36182.8.192.0/18182.8.192.1 to 182.8.255.254182.8.255.25516,382
37182.9.0.0/18182.9.0.1 to 182.9.63.254182.9.63.25516,382
38182.9.64.0/18182.9.64.1 to 182.9.127.254182.9.127.25516,382
39182.9.128.0/18182.9.128.1 to 182.9.191.254182.9.191.25516,382
40182.9.192.0/18182.9.192.1 to 182.9.255.254182.9.255.25516,382
41182.10.0.0/18182.10.0.1 to 182.10.63.254182.10.63.25516,382
42182.10.64.0/18182.10.64.1 to 182.10.127.254182.10.127.25516,382
43182.10.128.0/18182.10.128.1 to 182.10.191.254182.10.191.25516,382
44182.10.192.0/18182.10.192.1 to 182.10.255.254182.10.255.25516,382
45182.11.0.0/18182.11.0.1 to 182.11.63.254182.11.63.25516,382
46182.11.64.0/18182.11.64.1 to 182.11.127.254182.11.127.25516,382
47182.11.128.0/18182.11.128.1 to 182.11.191.254182.11.191.25516,382
48182.11.192.0/18182.11.192.1 to 182.11.255.254182.11.255.25516,382
49182.12.0.0/18182.12.0.1 to 182.12.63.254182.12.63.25516,382
50182.12.64.0/18182.12.64.1 to 182.12.127.254182.12.127.25516,382
51182.12.128.0/18182.12.128.1 to 182.12.191.254182.12.191.25516,382
52182.12.192.0/18182.12.192.1 to 182.12.255.254182.12.255.25516,382
53182.13.0.0/18182.13.0.1 to 182.13.63.254182.13.63.25516,382
54182.13.64.0/18182.13.64.1 to 182.13.127.254182.13.127.25516,382
55182.13.128.0/18182.13.128.1 to 182.13.191.254182.13.191.25516,382
56182.13.192.0/18182.13.192.1 to 182.13.255.254182.13.255.25516,382
57182.14.0.0/18182.14.0.1 to 182.14.63.254182.14.63.25516,382
58182.14.64.0/18182.14.64.1 to 182.14.127.254182.14.127.25516,382
59182.14.128.0/18182.14.128.1 to 182.14.191.254182.14.191.25516,382
60182.14.192.0/18182.14.192.1 to 182.14.255.254182.14.255.25516,382
61182.15.0.0/18182.15.0.1 to 182.15.63.254182.15.63.25516,382
62182.15.64.0/18182.15.64.1 to 182.15.127.254182.15.127.25516,382
63182.15.128.0/18182.15.128.1 to 182.15.191.254182.15.191.25516,382
64182.15.192.0/18182.15.192.1 to 182.15.255.254182.15.255.25516,382
65182.16.0.0/18182.16.0.1 to 182.16.63.254182.16.63.25516,382
66182.16.64.0/18182.16.64.1 to 182.16.127.254182.16.127.25516,382
67182.16.128.0/18182.16.128.1 to 182.16.191.254182.16.191.25516,382
68182.16.192.0/18182.16.192.1 to 182.16.255.254182.16.255.25516,382
69182.17.0.0/18182.17.0.1 to 182.17.63.254182.17.63.25516,382
70182.17.64.0/18182.17.64.1 to 182.17.127.254182.17.127.25516,382
71182.17.128.0/18182.17.128.1 to 182.17.191.254182.17.191.25516,382
72182.17.192.0/18182.17.192.1 to 182.17.255.254182.17.255.25516,382
73182.18.0.0/18182.18.0.1 to 182.18.63.254182.18.63.25516,382
74182.18.64.0/18182.18.64.1 to 182.18.127.254182.18.127.25516,382
75182.18.128.0/18182.18.128.1 to 182.18.191.254182.18.191.25516,382
76182.18.192.0/18182.18.192.1 to 182.18.255.254182.18.255.25516,382
77182.19.0.0/18182.19.0.1 to 182.19.63.254182.19.63.25516,382
78182.19.64.0/18182.19.64.1 to 182.19.127.254182.19.127.25516,382
79182.19.128.0/18182.19.128.1 to 182.19.191.254182.19.191.25516,382
80182.19.192.0/18182.19.192.1 to 182.19.255.254182.19.255.25516,382
81182.20.0.0/18182.20.0.1 to 182.20.63.254182.20.63.25516,382
82182.20.64.0/18182.20.64.1 to 182.20.127.254182.20.127.25516,382
83182.20.128.0/18182.20.128.1 to 182.20.191.254182.20.191.25516,382
84182.20.192.0/18182.20.192.1 to 182.20.255.254182.20.255.25516,382
85182.21.0.0/18182.21.0.1 to 182.21.63.254182.21.63.25516,382
86182.21.64.0/18182.21.64.1 to 182.21.127.254182.21.127.25516,382
87182.21.128.0/18182.21.128.1 to 182.21.191.254182.21.191.25516,382
88182.21.192.0/18182.21.192.1 to 182.21.255.254182.21.255.25516,382
89182.22.0.0/18182.22.0.1 to 182.22.63.254182.22.63.25516,382
90182.22.64.0/18182.22.64.1 to 182.22.127.254182.22.127.25516,382
91182.22.128.0/18182.22.128.1 to 182.22.191.254182.22.191.25516,382
92182.22.192.0/18182.22.192.1 to 182.22.255.254182.22.255.25516,382
93182.23.0.0/18182.23.0.1 to 182.23.63.254182.23.63.25516,382
94182.23.64.0/18182.23.64.1 to 182.23.127.254182.23.127.25516,382
95182.23.128.0/18182.23.128.1 to 182.23.191.254182.23.191.25516,382
96182.23.192.0/18182.23.192.1 to 182.23.255.254182.23.255.25516,382
97182.24.0.0/18182.24.0.1 to 182.24.63.254182.24.63.25516,382
98182.24.64.0/18182.24.64.1 to 182.24.127.254182.24.127.25516,382
99182.24.128.0/18182.24.128.1 to 182.24.191.254182.24.191.25516,382
100182.24.192.0/18182.24.192.1 to 182.24.255.254182.24.255.25516,382
101182.25.0.0/18182.25.0.1 to 182.25.63.254182.25.63.25516,382
102182.25.64.0/18182.25.64.1 to 182.25.127.254182.25.127.25516,382
103182.25.128.0/18182.25.128.1 to 182.25.191.254182.25.191.25516,382
104182.25.192.0/18182.25.192.1 to 182.25.255.254182.25.255.25516,382
105182.26.0.0/18182.26.0.1 to 182.26.63.254182.26.63.25516,382
106182.26.64.0/18182.26.64.1 to 182.26.127.254182.26.127.25516,382
107182.26.128.0/18182.26.128.1 to 182.26.191.254182.26.191.25516,382
108182.26.192.0/18182.26.192.1 to 182.26.255.254182.26.255.25516,382
109182.27.0.0/18182.27.0.1 to 182.27.63.254182.27.63.25516,382
110182.27.64.0/18182.27.64.1 to 182.27.127.254182.27.127.25516,382
111182.27.128.0/18182.27.128.1 to 182.27.191.254182.27.191.25516,382
112182.27.192.0/18182.27.192.1 to 182.27.255.254182.27.255.25516,382
113182.28.0.0/18182.28.0.1 to 182.28.63.254182.28.63.25516,382
114182.28.64.0/18182.28.64.1 to 182.28.127.254182.28.127.25516,382
115182.28.128.0/18182.28.128.1 to 182.28.191.254182.28.191.25516,382
116182.28.192.0/18182.28.192.1 to 182.28.255.254182.28.255.25516,382
117182.29.0.0/18182.29.0.1 to 182.29.63.254182.29.63.25516,382
118182.29.64.0/18182.29.64.1 to 182.29.127.254182.29.127.25516,382
119182.29.128.0/18182.29.128.1 to 182.29.191.254182.29.191.25516,382
120182.29.192.0/18182.29.192.1 to 182.29.255.254182.29.255.25516,382
121182.30.0.0/18182.30.0.1 to 182.30.63.254182.30.63.25516,382
122182.30.64.0/18182.30.64.1 to 182.30.127.254182.30.127.25516,382
123182.30.128.0/18182.30.128.1 to 182.30.191.254182.30.191.25516,382
124182.30.192.0/18182.30.192.1 to 182.30.255.254182.30.255.25516,382
125182.31.0.0/18182.31.0.1 to 182.31.63.254182.31.63.25516,382
126182.31.64.0/18182.31.64.1 to 182.31.127.254182.31.127.25516,382
127182.31.128.0/18182.31.128.1 to 182.31.191.254182.31.191.25516,382
128182.31.192.0/18182.31.192.1 to 182.31.255.254182.31.255.25516,382

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.