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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.

Network158.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
158.0.0.0
Broadcast address
158.255.255.255
First usable
158.0.0.1
Last usable
158.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex 9E000000 · Integer 2650800128 to 2667577343
Reverse DNS zone
158.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011110..00000000.00000000.00000000158.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10011110..00000000.00000000.00000000158.0.0.0
Broadcast10011110..11111111.11111111.11111111158.255.255.255
Split into smaller subnets/15
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

158.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1158.0.0.0/15158.0.0.1 to 158.1.255.254158.1.255.255131,070
2158.2.0.0/15158.2.0.1 to 158.3.255.254158.3.255.255131,070
3158.4.0.0/15158.4.0.1 to 158.5.255.254158.5.255.255131,070
4158.6.0.0/15158.6.0.1 to 158.7.255.254158.7.255.255131,070
5158.8.0.0/15158.8.0.1 to 158.9.255.254158.9.255.255131,070
6158.10.0.0/15158.10.0.1 to 158.11.255.254158.11.255.255131,070
7158.12.0.0/15158.12.0.1 to 158.13.255.254158.13.255.255131,070
8158.14.0.0/15158.14.0.1 to 158.15.255.254158.15.255.255131,070
9158.16.0.0/15158.16.0.1 to 158.17.255.254158.17.255.255131,070
10158.18.0.0/15158.18.0.1 to 158.19.255.254158.19.255.255131,070
11158.20.0.0/15158.20.0.1 to 158.21.255.254158.21.255.255131,070
12158.22.0.0/15158.22.0.1 to 158.23.255.254158.23.255.255131,070
13158.24.0.0/15158.24.0.1 to 158.25.255.254158.25.255.255131,070
14158.26.0.0/15158.26.0.1 to 158.27.255.254158.27.255.255131,070
15158.28.0.0/15158.28.0.1 to 158.29.255.254158.29.255.255131,070
16158.30.0.0/15158.30.0.1 to 158.31.255.254158.31.255.255131,070
17158.32.0.0/15158.32.0.1 to 158.33.255.254158.33.255.255131,070
18158.34.0.0/15158.34.0.1 to 158.35.255.254158.35.255.255131,070
19158.36.0.0/15158.36.0.1 to 158.37.255.254158.37.255.255131,070
20158.38.0.0/15158.38.0.1 to 158.39.255.254158.39.255.255131,070
21158.40.0.0/15158.40.0.1 to 158.41.255.254158.41.255.255131,070
22158.42.0.0/15158.42.0.1 to 158.43.255.254158.43.255.255131,070
23158.44.0.0/15158.44.0.1 to 158.45.255.254158.45.255.255131,070
24158.46.0.0/15158.46.0.1 to 158.47.255.254158.47.255.255131,070
25158.48.0.0/15158.48.0.1 to 158.49.255.254158.49.255.255131,070
26158.50.0.0/15158.50.0.1 to 158.51.255.254158.51.255.255131,070
27158.52.0.0/15158.52.0.1 to 158.53.255.254158.53.255.255131,070
28158.54.0.0/15158.54.0.1 to 158.55.255.254158.55.255.255131,070
29158.56.0.0/15158.56.0.1 to 158.57.255.254158.57.255.255131,070
30158.58.0.0/15158.58.0.1 to 158.59.255.254158.59.255.255131,070
31158.60.0.0/15158.60.0.1 to 158.61.255.254158.61.255.255131,070
32158.62.0.0/15158.62.0.1 to 158.63.255.254158.63.255.255131,070
33158.64.0.0/15158.64.0.1 to 158.65.255.254158.65.255.255131,070
34158.66.0.0/15158.66.0.1 to 158.67.255.254158.67.255.255131,070
35158.68.0.0/15158.68.0.1 to 158.69.255.254158.69.255.255131,070
36158.70.0.0/15158.70.0.1 to 158.71.255.254158.71.255.255131,070
37158.72.0.0/15158.72.0.1 to 158.73.255.254158.73.255.255131,070
38158.74.0.0/15158.74.0.1 to 158.75.255.254158.75.255.255131,070
39158.76.0.0/15158.76.0.1 to 158.77.255.254158.77.255.255131,070
40158.78.0.0/15158.78.0.1 to 158.79.255.254158.79.255.255131,070
41158.80.0.0/15158.80.0.1 to 158.81.255.254158.81.255.255131,070
42158.82.0.0/15158.82.0.1 to 158.83.255.254158.83.255.255131,070
43158.84.0.0/15158.84.0.1 to 158.85.255.254158.85.255.255131,070
44158.86.0.0/15158.86.0.1 to 158.87.255.254158.87.255.255131,070
45158.88.0.0/15158.88.0.1 to 158.89.255.254158.89.255.255131,070
46158.90.0.0/15158.90.0.1 to 158.91.255.254158.91.255.255131,070
47158.92.0.0/15158.92.0.1 to 158.93.255.254158.93.255.255131,070
48158.94.0.0/15158.94.0.1 to 158.95.255.254158.95.255.255131,070
49158.96.0.0/15158.96.0.1 to 158.97.255.254158.97.255.255131,070
50158.98.0.0/15158.98.0.1 to 158.99.255.254158.99.255.255131,070
51158.100.0.0/15158.100.0.1 to 158.101.255.254158.101.255.255131,070
52158.102.0.0/15158.102.0.1 to 158.103.255.254158.103.255.255131,070
53158.104.0.0/15158.104.0.1 to 158.105.255.254158.105.255.255131,070
54158.106.0.0/15158.106.0.1 to 158.107.255.254158.107.255.255131,070
55158.108.0.0/15158.108.0.1 to 158.109.255.254158.109.255.255131,070
56158.110.0.0/15158.110.0.1 to 158.111.255.254158.111.255.255131,070
57158.112.0.0/15158.112.0.1 to 158.113.255.254158.113.255.255131,070
58158.114.0.0/15158.114.0.1 to 158.115.255.254158.115.255.255131,070
59158.116.0.0/15158.116.0.1 to 158.117.255.254158.117.255.255131,070
60158.118.0.0/15158.118.0.1 to 158.119.255.254158.119.255.255131,070
61158.120.0.0/15158.120.0.1 to 158.121.255.254158.121.255.255131,070
62158.122.0.0/15158.122.0.1 to 158.123.255.254158.123.255.255131,070
63158.124.0.0/15158.124.0.1 to 158.125.255.254158.125.255.255131,070
64158.126.0.0/15158.126.0.1 to 158.127.255.254158.127.255.255131,070
65158.128.0.0/15158.128.0.1 to 158.129.255.254158.129.255.255131,070
66158.130.0.0/15158.130.0.1 to 158.131.255.254158.131.255.255131,070
67158.132.0.0/15158.132.0.1 to 158.133.255.254158.133.255.255131,070
68158.134.0.0/15158.134.0.1 to 158.135.255.254158.135.255.255131,070
69158.136.0.0/15158.136.0.1 to 158.137.255.254158.137.255.255131,070
70158.138.0.0/15158.138.0.1 to 158.139.255.254158.139.255.255131,070
71158.140.0.0/15158.140.0.1 to 158.141.255.254158.141.255.255131,070
72158.142.0.0/15158.142.0.1 to 158.143.255.254158.143.255.255131,070
73158.144.0.0/15158.144.0.1 to 158.145.255.254158.145.255.255131,070
74158.146.0.0/15158.146.0.1 to 158.147.255.254158.147.255.255131,070
75158.148.0.0/15158.148.0.1 to 158.149.255.254158.149.255.255131,070
76158.150.0.0/15158.150.0.1 to 158.151.255.254158.151.255.255131,070
77158.152.0.0/15158.152.0.1 to 158.153.255.254158.153.255.255131,070
78158.154.0.0/15158.154.0.1 to 158.155.255.254158.155.255.255131,070
79158.156.0.0/15158.156.0.1 to 158.157.255.254158.157.255.255131,070
80158.158.0.0/15158.158.0.1 to 158.159.255.254158.159.255.255131,070
81158.160.0.0/15158.160.0.1 to 158.161.255.254158.161.255.255131,070
82158.162.0.0/15158.162.0.1 to 158.163.255.254158.163.255.255131,070
83158.164.0.0/15158.164.0.1 to 158.165.255.254158.165.255.255131,070
84158.166.0.0/15158.166.0.1 to 158.167.255.254158.167.255.255131,070
85158.168.0.0/15158.168.0.1 to 158.169.255.254158.169.255.255131,070
86158.170.0.0/15158.170.0.1 to 158.171.255.254158.171.255.255131,070
87158.172.0.0/15158.172.0.1 to 158.173.255.254158.173.255.255131,070
88158.174.0.0/15158.174.0.1 to 158.175.255.254158.175.255.255131,070
89158.176.0.0/15158.176.0.1 to 158.177.255.254158.177.255.255131,070
90158.178.0.0/15158.178.0.1 to 158.179.255.254158.179.255.255131,070
91158.180.0.0/15158.180.0.1 to 158.181.255.254158.181.255.255131,070
92158.182.0.0/15158.182.0.1 to 158.183.255.254158.183.255.255131,070
93158.184.0.0/15158.184.0.1 to 158.185.255.254158.185.255.255131,070
94158.186.0.0/15158.186.0.1 to 158.187.255.254158.187.255.255131,070
95158.188.0.0/15158.188.0.1 to 158.189.255.254158.189.255.255131,070
96158.190.0.0/15158.190.0.1 to 158.191.255.254158.191.255.255131,070
97158.192.0.0/15158.192.0.1 to 158.193.255.254158.193.255.255131,070
98158.194.0.0/15158.194.0.1 to 158.195.255.254158.195.255.255131,070
99158.196.0.0/15158.196.0.1 to 158.197.255.254158.197.255.255131,070
100158.198.0.0/15158.198.0.1 to 158.199.255.254158.199.255.255131,070
101158.200.0.0/15158.200.0.1 to 158.201.255.254158.201.255.255131,070
102158.202.0.0/15158.202.0.1 to 158.203.255.254158.203.255.255131,070
103158.204.0.0/15158.204.0.1 to 158.205.255.254158.205.255.255131,070
104158.206.0.0/15158.206.0.1 to 158.207.255.254158.207.255.255131,070
105158.208.0.0/15158.208.0.1 to 158.209.255.254158.209.255.255131,070
106158.210.0.0/15158.210.0.1 to 158.211.255.254158.211.255.255131,070
107158.212.0.0/15158.212.0.1 to 158.213.255.254158.213.255.255131,070
108158.214.0.0/15158.214.0.1 to 158.215.255.254158.215.255.255131,070
109158.216.0.0/15158.216.0.1 to 158.217.255.254158.217.255.255131,070
110158.218.0.0/15158.218.0.1 to 158.219.255.254158.219.255.255131,070
111158.220.0.0/15158.220.0.1 to 158.221.255.254158.221.255.255131,070
112158.222.0.0/15158.222.0.1 to 158.223.255.254158.223.255.255131,070
113158.224.0.0/15158.224.0.1 to 158.225.255.254158.225.255.255131,070
114158.226.0.0/15158.226.0.1 to 158.227.255.254158.227.255.255131,070
115158.228.0.0/15158.228.0.1 to 158.229.255.254158.229.255.255131,070
116158.230.0.0/15158.230.0.1 to 158.231.255.254158.231.255.255131,070
117158.232.0.0/15158.232.0.1 to 158.233.255.254158.233.255.255131,070
118158.234.0.0/15158.234.0.1 to 158.235.255.254158.235.255.255131,070
119158.236.0.0/15158.236.0.1 to 158.237.255.254158.237.255.255131,070
120158.238.0.0/15158.238.0.1 to 158.239.255.254158.239.255.255131,070
121158.240.0.0/15158.240.0.1 to 158.241.255.254158.241.255.255131,070
122158.242.0.0/15158.242.0.1 to 158.243.255.254158.243.255.255131,070
123158.244.0.0/15158.244.0.1 to 158.245.255.254158.245.255.255131,070
124158.246.0.0/15158.246.0.1 to 158.247.255.254158.247.255.255131,070
125158.248.0.0/15158.248.0.1 to 158.249.255.254158.249.255.255131,070
126158.250.0.0/15158.250.0.1 to 158.251.255.254158.251.255.255131,070
127158.252.0.0/15158.252.0.1 to 158.253.255.254158.253.255.255131,070
128158.254.0.0/15158.254.0.1 to 158.255.255.254158.255.255.255131,070

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.