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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.

Network176.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
176.0.0.0
Broadcast address
177.255.255.255
First usable
176.0.0.1
Last usable
177.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex B0000000 · Integer 2952790016 to 2986344447
Reverse DNS zones
176.in-addr.arpa
177.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110000.00000000.00000000.00000000176.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10110000.00000000.00000000.00000000176.0.0.0
Broadcast10110001.11111111.11111111.11111111177.255.255.255
Split into smaller subnets/14
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

176.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1176.0.0.0/14176.0.0.1 to 176.3.255.254176.3.255.255262,142
2176.4.0.0/14176.4.0.1 to 176.7.255.254176.7.255.255262,142
3176.8.0.0/14176.8.0.1 to 176.11.255.254176.11.255.255262,142
4176.12.0.0/14176.12.0.1 to 176.15.255.254176.15.255.255262,142
5176.16.0.0/14176.16.0.1 to 176.19.255.254176.19.255.255262,142
6176.20.0.0/14176.20.0.1 to 176.23.255.254176.23.255.255262,142
7176.24.0.0/14176.24.0.1 to 176.27.255.254176.27.255.255262,142
8176.28.0.0/14176.28.0.1 to 176.31.255.254176.31.255.255262,142
9176.32.0.0/14176.32.0.1 to 176.35.255.254176.35.255.255262,142
10176.36.0.0/14176.36.0.1 to 176.39.255.254176.39.255.255262,142
11176.40.0.0/14176.40.0.1 to 176.43.255.254176.43.255.255262,142
12176.44.0.0/14176.44.0.1 to 176.47.255.254176.47.255.255262,142
13176.48.0.0/14176.48.0.1 to 176.51.255.254176.51.255.255262,142
14176.52.0.0/14176.52.0.1 to 176.55.255.254176.55.255.255262,142
15176.56.0.0/14176.56.0.1 to 176.59.255.254176.59.255.255262,142
16176.60.0.0/14176.60.0.1 to 176.63.255.254176.63.255.255262,142
17176.64.0.0/14176.64.0.1 to 176.67.255.254176.67.255.255262,142
18176.68.0.0/14176.68.0.1 to 176.71.255.254176.71.255.255262,142
19176.72.0.0/14176.72.0.1 to 176.75.255.254176.75.255.255262,142
20176.76.0.0/14176.76.0.1 to 176.79.255.254176.79.255.255262,142
21176.80.0.0/14176.80.0.1 to 176.83.255.254176.83.255.255262,142
22176.84.0.0/14176.84.0.1 to 176.87.255.254176.87.255.255262,142
23176.88.0.0/14176.88.0.1 to 176.91.255.254176.91.255.255262,142
24176.92.0.0/14176.92.0.1 to 176.95.255.254176.95.255.255262,142
25176.96.0.0/14176.96.0.1 to 176.99.255.254176.99.255.255262,142
26176.100.0.0/14176.100.0.1 to 176.103.255.254176.103.255.255262,142
27176.104.0.0/14176.104.0.1 to 176.107.255.254176.107.255.255262,142
28176.108.0.0/14176.108.0.1 to 176.111.255.254176.111.255.255262,142
29176.112.0.0/14176.112.0.1 to 176.115.255.254176.115.255.255262,142
30176.116.0.0/14176.116.0.1 to 176.119.255.254176.119.255.255262,142
31176.120.0.0/14176.120.0.1 to 176.123.255.254176.123.255.255262,142
32176.124.0.0/14176.124.0.1 to 176.127.255.254176.127.255.255262,142
33176.128.0.0/14176.128.0.1 to 176.131.255.254176.131.255.255262,142
34176.132.0.0/14176.132.0.1 to 176.135.255.254176.135.255.255262,142
35176.136.0.0/14176.136.0.1 to 176.139.255.254176.139.255.255262,142
36176.140.0.0/14176.140.0.1 to 176.143.255.254176.143.255.255262,142
37176.144.0.0/14176.144.0.1 to 176.147.255.254176.147.255.255262,142
38176.148.0.0/14176.148.0.1 to 176.151.255.254176.151.255.255262,142
39176.152.0.0/14176.152.0.1 to 176.155.255.254176.155.255.255262,142
40176.156.0.0/14176.156.0.1 to 176.159.255.254176.159.255.255262,142
41176.160.0.0/14176.160.0.1 to 176.163.255.254176.163.255.255262,142
42176.164.0.0/14176.164.0.1 to 176.167.255.254176.167.255.255262,142
43176.168.0.0/14176.168.0.1 to 176.171.255.254176.171.255.255262,142
44176.172.0.0/14176.172.0.1 to 176.175.255.254176.175.255.255262,142
45176.176.0.0/14176.176.0.1 to 176.179.255.254176.179.255.255262,142
46176.180.0.0/14176.180.0.1 to 176.183.255.254176.183.255.255262,142
47176.184.0.0/14176.184.0.1 to 176.187.255.254176.187.255.255262,142
48176.188.0.0/14176.188.0.1 to 176.191.255.254176.191.255.255262,142
49176.192.0.0/14176.192.0.1 to 176.195.255.254176.195.255.255262,142
50176.196.0.0/14176.196.0.1 to 176.199.255.254176.199.255.255262,142
51176.200.0.0/14176.200.0.1 to 176.203.255.254176.203.255.255262,142
52176.204.0.0/14176.204.0.1 to 176.207.255.254176.207.255.255262,142
53176.208.0.0/14176.208.0.1 to 176.211.255.254176.211.255.255262,142
54176.212.0.0/14176.212.0.1 to 176.215.255.254176.215.255.255262,142
55176.216.0.0/14176.216.0.1 to 176.219.255.254176.219.255.255262,142
56176.220.0.0/14176.220.0.1 to 176.223.255.254176.223.255.255262,142
57176.224.0.0/14176.224.0.1 to 176.227.255.254176.227.255.255262,142
58176.228.0.0/14176.228.0.1 to 176.231.255.254176.231.255.255262,142
59176.232.0.0/14176.232.0.1 to 176.235.255.254176.235.255.255262,142
60176.236.0.0/14176.236.0.1 to 176.239.255.254176.239.255.255262,142
61176.240.0.0/14176.240.0.1 to 176.243.255.254176.243.255.255262,142
62176.244.0.0/14176.244.0.1 to 176.247.255.254176.247.255.255262,142
63176.248.0.0/14176.248.0.1 to 176.251.255.254176.251.255.255262,142
64176.252.0.0/14176.252.0.1 to 176.255.255.254176.255.255.255262,142
65177.0.0.0/14177.0.0.1 to 177.3.255.254177.3.255.255262,142
66177.4.0.0/14177.4.0.1 to 177.7.255.254177.7.255.255262,142
67177.8.0.0/14177.8.0.1 to 177.11.255.254177.11.255.255262,142
68177.12.0.0/14177.12.0.1 to 177.15.255.254177.15.255.255262,142
69177.16.0.0/14177.16.0.1 to 177.19.255.254177.19.255.255262,142
70177.20.0.0/14177.20.0.1 to 177.23.255.254177.23.255.255262,142
71177.24.0.0/14177.24.0.1 to 177.27.255.254177.27.255.255262,142
72177.28.0.0/14177.28.0.1 to 177.31.255.254177.31.255.255262,142
73177.32.0.0/14177.32.0.1 to 177.35.255.254177.35.255.255262,142
74177.36.0.0/14177.36.0.1 to 177.39.255.254177.39.255.255262,142
75177.40.0.0/14177.40.0.1 to 177.43.255.254177.43.255.255262,142
76177.44.0.0/14177.44.0.1 to 177.47.255.254177.47.255.255262,142
77177.48.0.0/14177.48.0.1 to 177.51.255.254177.51.255.255262,142
78177.52.0.0/14177.52.0.1 to 177.55.255.254177.55.255.255262,142
79177.56.0.0/14177.56.0.1 to 177.59.255.254177.59.255.255262,142
80177.60.0.0/14177.60.0.1 to 177.63.255.254177.63.255.255262,142
81177.64.0.0/14177.64.0.1 to 177.67.255.254177.67.255.255262,142
82177.68.0.0/14177.68.0.1 to 177.71.255.254177.71.255.255262,142
83177.72.0.0/14177.72.0.1 to 177.75.255.254177.75.255.255262,142
84177.76.0.0/14177.76.0.1 to 177.79.255.254177.79.255.255262,142
85177.80.0.0/14177.80.0.1 to 177.83.255.254177.83.255.255262,142
86177.84.0.0/14177.84.0.1 to 177.87.255.254177.87.255.255262,142
87177.88.0.0/14177.88.0.1 to 177.91.255.254177.91.255.255262,142
88177.92.0.0/14177.92.0.1 to 177.95.255.254177.95.255.255262,142
89177.96.0.0/14177.96.0.1 to 177.99.255.254177.99.255.255262,142
90177.100.0.0/14177.100.0.1 to 177.103.255.254177.103.255.255262,142
91177.104.0.0/14177.104.0.1 to 177.107.255.254177.107.255.255262,142
92177.108.0.0/14177.108.0.1 to 177.111.255.254177.111.255.255262,142
93177.112.0.0/14177.112.0.1 to 177.115.255.254177.115.255.255262,142
94177.116.0.0/14177.116.0.1 to 177.119.255.254177.119.255.255262,142
95177.120.0.0/14177.120.0.1 to 177.123.255.254177.123.255.255262,142
96177.124.0.0/14177.124.0.1 to 177.127.255.254177.127.255.255262,142
97177.128.0.0/14177.128.0.1 to 177.131.255.254177.131.255.255262,142
98177.132.0.0/14177.132.0.1 to 177.135.255.254177.135.255.255262,142
99177.136.0.0/14177.136.0.1 to 177.139.255.254177.139.255.255262,142
100177.140.0.0/14177.140.0.1 to 177.143.255.254177.143.255.255262,142
101177.144.0.0/14177.144.0.1 to 177.147.255.254177.147.255.255262,142
102177.148.0.0/14177.148.0.1 to 177.151.255.254177.151.255.255262,142
103177.152.0.0/14177.152.0.1 to 177.155.255.254177.155.255.255262,142
104177.156.0.0/14177.156.0.1 to 177.159.255.254177.159.255.255262,142
105177.160.0.0/14177.160.0.1 to 177.163.255.254177.163.255.255262,142
106177.164.0.0/14177.164.0.1 to 177.167.255.254177.167.255.255262,142
107177.168.0.0/14177.168.0.1 to 177.171.255.254177.171.255.255262,142
108177.172.0.0/14177.172.0.1 to 177.175.255.254177.175.255.255262,142
109177.176.0.0/14177.176.0.1 to 177.179.255.254177.179.255.255262,142
110177.180.0.0/14177.180.0.1 to 177.183.255.254177.183.255.255262,142
111177.184.0.0/14177.184.0.1 to 177.187.255.254177.187.255.255262,142
112177.188.0.0/14177.188.0.1 to 177.191.255.254177.191.255.255262,142
113177.192.0.0/14177.192.0.1 to 177.195.255.254177.195.255.255262,142
114177.196.0.0/14177.196.0.1 to 177.199.255.254177.199.255.255262,142
115177.200.0.0/14177.200.0.1 to 177.203.255.254177.203.255.255262,142
116177.204.0.0/14177.204.0.1 to 177.207.255.254177.207.255.255262,142
117177.208.0.0/14177.208.0.1 to 177.211.255.254177.211.255.255262,142
118177.212.0.0/14177.212.0.1 to 177.215.255.254177.215.255.255262,142
119177.216.0.0/14177.216.0.1 to 177.219.255.254177.219.255.255262,142
120177.220.0.0/14177.220.0.1 to 177.223.255.254177.223.255.255262,142
121177.224.0.0/14177.224.0.1 to 177.227.255.254177.227.255.255262,142
122177.228.0.0/14177.228.0.1 to 177.231.255.254177.231.255.255262,142
123177.232.0.0/14177.232.0.1 to 177.235.255.254177.235.255.255262,142
124177.236.0.0/14177.236.0.1 to 177.239.255.254177.239.255.255262,142
125177.240.0.0/14177.240.0.1 to 177.243.255.254177.243.255.255262,142
126177.244.0.0/14177.244.0.1 to 177.247.255.254177.247.255.255262,142
127177.248.0.0/14177.248.0.1 to 177.251.255.254177.251.255.255262,142
128177.252.0.0/14177.252.0.1 to 177.255.255.254177.255.255.255262,142

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.