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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.

Network176.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
176.0.0.0
Broadcast address
179.255.255.255
First usable
176.0.0.1
Last usable
179.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
B (default /16)
As numbers
Hex B0000000 · Integer 2952790016 to 3019898879
Reverse DNS zones
176.in-addr.arpa
177.in-addr.arpa
178.in-addr.arpa
179.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110000.00000000.00000000.00000000176.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10110000.00000000.00000000.00000000176.0.0.0
Broadcast10110011.11111111.11111111.11111111179.255.255.255
Split into smaller subnets/13
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

176.0.0.0/6 makes 128 subnets of /13.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1176.0.0.0/13176.0.0.1 to 176.7.255.254176.7.255.255524,286
2176.8.0.0/13176.8.0.1 to 176.15.255.254176.15.255.255524,286
3176.16.0.0/13176.16.0.1 to 176.23.255.254176.23.255.255524,286
4176.24.0.0/13176.24.0.1 to 176.31.255.254176.31.255.255524,286
5176.32.0.0/13176.32.0.1 to 176.39.255.254176.39.255.255524,286
6176.40.0.0/13176.40.0.1 to 176.47.255.254176.47.255.255524,286
7176.48.0.0/13176.48.0.1 to 176.55.255.254176.55.255.255524,286
8176.56.0.0/13176.56.0.1 to 176.63.255.254176.63.255.255524,286
9176.64.0.0/13176.64.0.1 to 176.71.255.254176.71.255.255524,286
10176.72.0.0/13176.72.0.1 to 176.79.255.254176.79.255.255524,286
11176.80.0.0/13176.80.0.1 to 176.87.255.254176.87.255.255524,286
12176.88.0.0/13176.88.0.1 to 176.95.255.254176.95.255.255524,286
13176.96.0.0/13176.96.0.1 to 176.103.255.254176.103.255.255524,286
14176.104.0.0/13176.104.0.1 to 176.111.255.254176.111.255.255524,286
15176.112.0.0/13176.112.0.1 to 176.119.255.254176.119.255.255524,286
16176.120.0.0/13176.120.0.1 to 176.127.255.254176.127.255.255524,286
17176.128.0.0/13176.128.0.1 to 176.135.255.254176.135.255.255524,286
18176.136.0.0/13176.136.0.1 to 176.143.255.254176.143.255.255524,286
19176.144.0.0/13176.144.0.1 to 176.151.255.254176.151.255.255524,286
20176.152.0.0/13176.152.0.1 to 176.159.255.254176.159.255.255524,286
21176.160.0.0/13176.160.0.1 to 176.167.255.254176.167.255.255524,286
22176.168.0.0/13176.168.0.1 to 176.175.255.254176.175.255.255524,286
23176.176.0.0/13176.176.0.1 to 176.183.255.254176.183.255.255524,286
24176.184.0.0/13176.184.0.1 to 176.191.255.254176.191.255.255524,286
25176.192.0.0/13176.192.0.1 to 176.199.255.254176.199.255.255524,286
26176.200.0.0/13176.200.0.1 to 176.207.255.254176.207.255.255524,286
27176.208.0.0/13176.208.0.1 to 176.215.255.254176.215.255.255524,286
28176.216.0.0/13176.216.0.1 to 176.223.255.254176.223.255.255524,286
29176.224.0.0/13176.224.0.1 to 176.231.255.254176.231.255.255524,286
30176.232.0.0/13176.232.0.1 to 176.239.255.254176.239.255.255524,286
31176.240.0.0/13176.240.0.1 to 176.247.255.254176.247.255.255524,286
32176.248.0.0/13176.248.0.1 to 176.255.255.254176.255.255.255524,286
33177.0.0.0/13177.0.0.1 to 177.7.255.254177.7.255.255524,286
34177.8.0.0/13177.8.0.1 to 177.15.255.254177.15.255.255524,286
35177.16.0.0/13177.16.0.1 to 177.23.255.254177.23.255.255524,286
36177.24.0.0/13177.24.0.1 to 177.31.255.254177.31.255.255524,286
37177.32.0.0/13177.32.0.1 to 177.39.255.254177.39.255.255524,286
38177.40.0.0/13177.40.0.1 to 177.47.255.254177.47.255.255524,286
39177.48.0.0/13177.48.0.1 to 177.55.255.254177.55.255.255524,286
40177.56.0.0/13177.56.0.1 to 177.63.255.254177.63.255.255524,286
41177.64.0.0/13177.64.0.1 to 177.71.255.254177.71.255.255524,286
42177.72.0.0/13177.72.0.1 to 177.79.255.254177.79.255.255524,286
43177.80.0.0/13177.80.0.1 to 177.87.255.254177.87.255.255524,286
44177.88.0.0/13177.88.0.1 to 177.95.255.254177.95.255.255524,286
45177.96.0.0/13177.96.0.1 to 177.103.255.254177.103.255.255524,286
46177.104.0.0/13177.104.0.1 to 177.111.255.254177.111.255.255524,286
47177.112.0.0/13177.112.0.1 to 177.119.255.254177.119.255.255524,286
48177.120.0.0/13177.120.0.1 to 177.127.255.254177.127.255.255524,286
49177.128.0.0/13177.128.0.1 to 177.135.255.254177.135.255.255524,286
50177.136.0.0/13177.136.0.1 to 177.143.255.254177.143.255.255524,286
51177.144.0.0/13177.144.0.1 to 177.151.255.254177.151.255.255524,286
52177.152.0.0/13177.152.0.1 to 177.159.255.254177.159.255.255524,286
53177.160.0.0/13177.160.0.1 to 177.167.255.254177.167.255.255524,286
54177.168.0.0/13177.168.0.1 to 177.175.255.254177.175.255.255524,286
55177.176.0.0/13177.176.0.1 to 177.183.255.254177.183.255.255524,286
56177.184.0.0/13177.184.0.1 to 177.191.255.254177.191.255.255524,286
57177.192.0.0/13177.192.0.1 to 177.199.255.254177.199.255.255524,286
58177.200.0.0/13177.200.0.1 to 177.207.255.254177.207.255.255524,286
59177.208.0.0/13177.208.0.1 to 177.215.255.254177.215.255.255524,286
60177.216.0.0/13177.216.0.1 to 177.223.255.254177.223.255.255524,286
61177.224.0.0/13177.224.0.1 to 177.231.255.254177.231.255.255524,286
62177.232.0.0/13177.232.0.1 to 177.239.255.254177.239.255.255524,286
63177.240.0.0/13177.240.0.1 to 177.247.255.254177.247.255.255524,286
64177.248.0.0/13177.248.0.1 to 177.255.255.254177.255.255.255524,286
65178.0.0.0/13178.0.0.1 to 178.7.255.254178.7.255.255524,286
66178.8.0.0/13178.8.0.1 to 178.15.255.254178.15.255.255524,286
67178.16.0.0/13178.16.0.1 to 178.23.255.254178.23.255.255524,286
68178.24.0.0/13178.24.0.1 to 178.31.255.254178.31.255.255524,286
69178.32.0.0/13178.32.0.1 to 178.39.255.254178.39.255.255524,286
70178.40.0.0/13178.40.0.1 to 178.47.255.254178.47.255.255524,286
71178.48.0.0/13178.48.0.1 to 178.55.255.254178.55.255.255524,286
72178.56.0.0/13178.56.0.1 to 178.63.255.254178.63.255.255524,286
73178.64.0.0/13178.64.0.1 to 178.71.255.254178.71.255.255524,286
74178.72.0.0/13178.72.0.1 to 178.79.255.254178.79.255.255524,286
75178.80.0.0/13178.80.0.1 to 178.87.255.254178.87.255.255524,286
76178.88.0.0/13178.88.0.1 to 178.95.255.254178.95.255.255524,286
77178.96.0.0/13178.96.0.1 to 178.103.255.254178.103.255.255524,286
78178.104.0.0/13178.104.0.1 to 178.111.255.254178.111.255.255524,286
79178.112.0.0/13178.112.0.1 to 178.119.255.254178.119.255.255524,286
80178.120.0.0/13178.120.0.1 to 178.127.255.254178.127.255.255524,286
81178.128.0.0/13178.128.0.1 to 178.135.255.254178.135.255.255524,286
82178.136.0.0/13178.136.0.1 to 178.143.255.254178.143.255.255524,286
83178.144.0.0/13178.144.0.1 to 178.151.255.254178.151.255.255524,286
84178.152.0.0/13178.152.0.1 to 178.159.255.254178.159.255.255524,286
85178.160.0.0/13178.160.0.1 to 178.167.255.254178.167.255.255524,286
86178.168.0.0/13178.168.0.1 to 178.175.255.254178.175.255.255524,286
87178.176.0.0/13178.176.0.1 to 178.183.255.254178.183.255.255524,286
88178.184.0.0/13178.184.0.1 to 178.191.255.254178.191.255.255524,286
89178.192.0.0/13178.192.0.1 to 178.199.255.254178.199.255.255524,286
90178.200.0.0/13178.200.0.1 to 178.207.255.254178.207.255.255524,286
91178.208.0.0/13178.208.0.1 to 178.215.255.254178.215.255.255524,286
92178.216.0.0/13178.216.0.1 to 178.223.255.254178.223.255.255524,286
93178.224.0.0/13178.224.0.1 to 178.231.255.254178.231.255.255524,286
94178.232.0.0/13178.232.0.1 to 178.239.255.254178.239.255.255524,286
95178.240.0.0/13178.240.0.1 to 178.247.255.254178.247.255.255524,286
96178.248.0.0/13178.248.0.1 to 178.255.255.254178.255.255.255524,286
97179.0.0.0/13179.0.0.1 to 179.7.255.254179.7.255.255524,286
98179.8.0.0/13179.8.0.1 to 179.15.255.254179.15.255.255524,286
99179.16.0.0/13179.16.0.1 to 179.23.255.254179.23.255.255524,286
100179.24.0.0/13179.24.0.1 to 179.31.255.254179.31.255.255524,286
101179.32.0.0/13179.32.0.1 to 179.39.255.254179.39.255.255524,286
102179.40.0.0/13179.40.0.1 to 179.47.255.254179.47.255.255524,286
103179.48.0.0/13179.48.0.1 to 179.55.255.254179.55.255.255524,286
104179.56.0.0/13179.56.0.1 to 179.63.255.254179.63.255.255524,286
105179.64.0.0/13179.64.0.1 to 179.71.255.254179.71.255.255524,286
106179.72.0.0/13179.72.0.1 to 179.79.255.254179.79.255.255524,286
107179.80.0.0/13179.80.0.1 to 179.87.255.254179.87.255.255524,286
108179.88.0.0/13179.88.0.1 to 179.95.255.254179.95.255.255524,286
109179.96.0.0/13179.96.0.1 to 179.103.255.254179.103.255.255524,286
110179.104.0.0/13179.104.0.1 to 179.111.255.254179.111.255.255524,286
111179.112.0.0/13179.112.0.1 to 179.119.255.254179.119.255.255524,286
112179.120.0.0/13179.120.0.1 to 179.127.255.254179.127.255.255524,286
113179.128.0.0/13179.128.0.1 to 179.135.255.254179.135.255.255524,286
114179.136.0.0/13179.136.0.1 to 179.143.255.254179.143.255.255524,286
115179.144.0.0/13179.144.0.1 to 179.151.255.254179.151.255.255524,286
116179.152.0.0/13179.152.0.1 to 179.159.255.254179.159.255.255524,286
117179.160.0.0/13179.160.0.1 to 179.167.255.254179.167.255.255524,286
118179.168.0.0/13179.168.0.1 to 179.175.255.254179.175.255.255524,286
119179.176.0.0/13179.176.0.1 to 179.183.255.254179.183.255.255524,286
120179.184.0.0/13179.184.0.1 to 179.191.255.254179.191.255.255524,286
121179.192.0.0/13179.192.0.1 to 179.199.255.254179.199.255.255524,286
122179.200.0.0/13179.200.0.1 to 179.207.255.254179.207.255.255524,286
123179.208.0.0/13179.208.0.1 to 179.215.255.254179.215.255.255524,286
124179.216.0.0/13179.216.0.1 to 179.223.255.254179.223.255.255524,286
125179.224.0.0/13179.224.0.1 to 179.231.255.254179.231.255.255524,286
126179.232.0.0/13179.232.0.1 to 179.239.255.254179.239.255.255524,286
127179.240.0.0/13179.240.0.1 to 179.247.255.254179.247.255.255524,286
128179.248.0.0/13179.248.0.1 to 179.255.255.254179.255.255.255524,286

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.