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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.

Network154.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
154.0.0.0
Broadcast address
154.255.255.255
First usable
154.0.0.1
Last usable
154.255.255.254
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 9A000000 · Integer 2583691264 to 2600468479
Reverse DNS zone
154.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011010..00000000.00000000.00000000154.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10011010..00000000.00000000.00000000154.0.0.0
Broadcast10011010..11111111.11111111.11111111154.255.255.255
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)

154.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1154.0.0.0/15154.0.0.1 to 154.1.255.254154.1.255.255131,070
2154.2.0.0/15154.2.0.1 to 154.3.255.254154.3.255.255131,070
3154.4.0.0/15154.4.0.1 to 154.5.255.254154.5.255.255131,070
4154.6.0.0/15154.6.0.1 to 154.7.255.254154.7.255.255131,070
5154.8.0.0/15154.8.0.1 to 154.9.255.254154.9.255.255131,070
6154.10.0.0/15154.10.0.1 to 154.11.255.254154.11.255.255131,070
7154.12.0.0/15154.12.0.1 to 154.13.255.254154.13.255.255131,070
8154.14.0.0/15154.14.0.1 to 154.15.255.254154.15.255.255131,070
9154.16.0.0/15154.16.0.1 to 154.17.255.254154.17.255.255131,070
10154.18.0.0/15154.18.0.1 to 154.19.255.254154.19.255.255131,070
11154.20.0.0/15154.20.0.1 to 154.21.255.254154.21.255.255131,070
12154.22.0.0/15154.22.0.1 to 154.23.255.254154.23.255.255131,070
13154.24.0.0/15154.24.0.1 to 154.25.255.254154.25.255.255131,070
14154.26.0.0/15154.26.0.1 to 154.27.255.254154.27.255.255131,070
15154.28.0.0/15154.28.0.1 to 154.29.255.254154.29.255.255131,070
16154.30.0.0/15154.30.0.1 to 154.31.255.254154.31.255.255131,070
17154.32.0.0/15154.32.0.1 to 154.33.255.254154.33.255.255131,070
18154.34.0.0/15154.34.0.1 to 154.35.255.254154.35.255.255131,070
19154.36.0.0/15154.36.0.1 to 154.37.255.254154.37.255.255131,070
20154.38.0.0/15154.38.0.1 to 154.39.255.254154.39.255.255131,070
21154.40.0.0/15154.40.0.1 to 154.41.255.254154.41.255.255131,070
22154.42.0.0/15154.42.0.1 to 154.43.255.254154.43.255.255131,070
23154.44.0.0/15154.44.0.1 to 154.45.255.254154.45.255.255131,070
24154.46.0.0/15154.46.0.1 to 154.47.255.254154.47.255.255131,070
25154.48.0.0/15154.48.0.1 to 154.49.255.254154.49.255.255131,070
26154.50.0.0/15154.50.0.1 to 154.51.255.254154.51.255.255131,070
27154.52.0.0/15154.52.0.1 to 154.53.255.254154.53.255.255131,070
28154.54.0.0/15154.54.0.1 to 154.55.255.254154.55.255.255131,070
29154.56.0.0/15154.56.0.1 to 154.57.255.254154.57.255.255131,070
30154.58.0.0/15154.58.0.1 to 154.59.255.254154.59.255.255131,070
31154.60.0.0/15154.60.0.1 to 154.61.255.254154.61.255.255131,070
32154.62.0.0/15154.62.0.1 to 154.63.255.254154.63.255.255131,070
33154.64.0.0/15154.64.0.1 to 154.65.255.254154.65.255.255131,070
34154.66.0.0/15154.66.0.1 to 154.67.255.254154.67.255.255131,070
35154.68.0.0/15154.68.0.1 to 154.69.255.254154.69.255.255131,070
36154.70.0.0/15154.70.0.1 to 154.71.255.254154.71.255.255131,070
37154.72.0.0/15154.72.0.1 to 154.73.255.254154.73.255.255131,070
38154.74.0.0/15154.74.0.1 to 154.75.255.254154.75.255.255131,070
39154.76.0.0/15154.76.0.1 to 154.77.255.254154.77.255.255131,070
40154.78.0.0/15154.78.0.1 to 154.79.255.254154.79.255.255131,070
41154.80.0.0/15154.80.0.1 to 154.81.255.254154.81.255.255131,070
42154.82.0.0/15154.82.0.1 to 154.83.255.254154.83.255.255131,070
43154.84.0.0/15154.84.0.1 to 154.85.255.254154.85.255.255131,070
44154.86.0.0/15154.86.0.1 to 154.87.255.254154.87.255.255131,070
45154.88.0.0/15154.88.0.1 to 154.89.255.254154.89.255.255131,070
46154.90.0.0/15154.90.0.1 to 154.91.255.254154.91.255.255131,070
47154.92.0.0/15154.92.0.1 to 154.93.255.254154.93.255.255131,070
48154.94.0.0/15154.94.0.1 to 154.95.255.254154.95.255.255131,070
49154.96.0.0/15154.96.0.1 to 154.97.255.254154.97.255.255131,070
50154.98.0.0/15154.98.0.1 to 154.99.255.254154.99.255.255131,070
51154.100.0.0/15154.100.0.1 to 154.101.255.254154.101.255.255131,070
52154.102.0.0/15154.102.0.1 to 154.103.255.254154.103.255.255131,070
53154.104.0.0/15154.104.0.1 to 154.105.255.254154.105.255.255131,070
54154.106.0.0/15154.106.0.1 to 154.107.255.254154.107.255.255131,070
55154.108.0.0/15154.108.0.1 to 154.109.255.254154.109.255.255131,070
56154.110.0.0/15154.110.0.1 to 154.111.255.254154.111.255.255131,070
57154.112.0.0/15154.112.0.1 to 154.113.255.254154.113.255.255131,070
58154.114.0.0/15154.114.0.1 to 154.115.255.254154.115.255.255131,070
59154.116.0.0/15154.116.0.1 to 154.117.255.254154.117.255.255131,070
60154.118.0.0/15154.118.0.1 to 154.119.255.254154.119.255.255131,070
61154.120.0.0/15154.120.0.1 to 154.121.255.254154.121.255.255131,070
62154.122.0.0/15154.122.0.1 to 154.123.255.254154.123.255.255131,070
63154.124.0.0/15154.124.0.1 to 154.125.255.254154.125.255.255131,070
64154.126.0.0/15154.126.0.1 to 154.127.255.254154.127.255.255131,070
65154.128.0.0/15154.128.0.1 to 154.129.255.254154.129.255.255131,070
66154.130.0.0/15154.130.0.1 to 154.131.255.254154.131.255.255131,070
67154.132.0.0/15154.132.0.1 to 154.133.255.254154.133.255.255131,070
68154.134.0.0/15154.134.0.1 to 154.135.255.254154.135.255.255131,070
69154.136.0.0/15154.136.0.1 to 154.137.255.254154.137.255.255131,070
70154.138.0.0/15154.138.0.1 to 154.139.255.254154.139.255.255131,070
71154.140.0.0/15154.140.0.1 to 154.141.255.254154.141.255.255131,070
72154.142.0.0/15154.142.0.1 to 154.143.255.254154.143.255.255131,070
73154.144.0.0/15154.144.0.1 to 154.145.255.254154.145.255.255131,070
74154.146.0.0/15154.146.0.1 to 154.147.255.254154.147.255.255131,070
75154.148.0.0/15154.148.0.1 to 154.149.255.254154.149.255.255131,070
76154.150.0.0/15154.150.0.1 to 154.151.255.254154.151.255.255131,070
77154.152.0.0/15154.152.0.1 to 154.153.255.254154.153.255.255131,070
78154.154.0.0/15154.154.0.1 to 154.155.255.254154.155.255.255131,070
79154.156.0.0/15154.156.0.1 to 154.157.255.254154.157.255.255131,070
80154.158.0.0/15154.158.0.1 to 154.159.255.254154.159.255.255131,070
81154.160.0.0/15154.160.0.1 to 154.161.255.254154.161.255.255131,070
82154.162.0.0/15154.162.0.1 to 154.163.255.254154.163.255.255131,070
83154.164.0.0/15154.164.0.1 to 154.165.255.254154.165.255.255131,070
84154.166.0.0/15154.166.0.1 to 154.167.255.254154.167.255.255131,070
85154.168.0.0/15154.168.0.1 to 154.169.255.254154.169.255.255131,070
86154.170.0.0/15154.170.0.1 to 154.171.255.254154.171.255.255131,070
87154.172.0.0/15154.172.0.1 to 154.173.255.254154.173.255.255131,070
88154.174.0.0/15154.174.0.1 to 154.175.255.254154.175.255.255131,070
89154.176.0.0/15154.176.0.1 to 154.177.255.254154.177.255.255131,070
90154.178.0.0/15154.178.0.1 to 154.179.255.254154.179.255.255131,070
91154.180.0.0/15154.180.0.1 to 154.181.255.254154.181.255.255131,070
92154.182.0.0/15154.182.0.1 to 154.183.255.254154.183.255.255131,070
93154.184.0.0/15154.184.0.1 to 154.185.255.254154.185.255.255131,070
94154.186.0.0/15154.186.0.1 to 154.187.255.254154.187.255.255131,070
95154.188.0.0/15154.188.0.1 to 154.189.255.254154.189.255.255131,070
96154.190.0.0/15154.190.0.1 to 154.191.255.254154.191.255.255131,070
97154.192.0.0/15154.192.0.1 to 154.193.255.254154.193.255.255131,070
98154.194.0.0/15154.194.0.1 to 154.195.255.254154.195.255.255131,070
99154.196.0.0/15154.196.0.1 to 154.197.255.254154.197.255.255131,070
100154.198.0.0/15154.198.0.1 to 154.199.255.254154.199.255.255131,070
101154.200.0.0/15154.200.0.1 to 154.201.255.254154.201.255.255131,070
102154.202.0.0/15154.202.0.1 to 154.203.255.254154.203.255.255131,070
103154.204.0.0/15154.204.0.1 to 154.205.255.254154.205.255.255131,070
104154.206.0.0/15154.206.0.1 to 154.207.255.254154.207.255.255131,070
105154.208.0.0/15154.208.0.1 to 154.209.255.254154.209.255.255131,070
106154.210.0.0/15154.210.0.1 to 154.211.255.254154.211.255.255131,070
107154.212.0.0/15154.212.0.1 to 154.213.255.254154.213.255.255131,070
108154.214.0.0/15154.214.0.1 to 154.215.255.254154.215.255.255131,070
109154.216.0.0/15154.216.0.1 to 154.217.255.254154.217.255.255131,070
110154.218.0.0/15154.218.0.1 to 154.219.255.254154.219.255.255131,070
111154.220.0.0/15154.220.0.1 to 154.221.255.254154.221.255.255131,070
112154.222.0.0/15154.222.0.1 to 154.223.255.254154.223.255.255131,070
113154.224.0.0/15154.224.0.1 to 154.225.255.254154.225.255.255131,070
114154.226.0.0/15154.226.0.1 to 154.227.255.254154.227.255.255131,070
115154.228.0.0/15154.228.0.1 to 154.229.255.254154.229.255.255131,070
116154.230.0.0/15154.230.0.1 to 154.231.255.254154.231.255.255131,070
117154.232.0.0/15154.232.0.1 to 154.233.255.254154.233.255.255131,070
118154.234.0.0/15154.234.0.1 to 154.235.255.254154.235.255.255131,070
119154.236.0.0/15154.236.0.1 to 154.237.255.254154.237.255.255131,070
120154.238.0.0/15154.238.0.1 to 154.239.255.254154.239.255.255131,070
121154.240.0.0/15154.240.0.1 to 154.241.255.254154.241.255.255131,070
122154.242.0.0/15154.242.0.1 to 154.243.255.254154.243.255.255131,070
123154.244.0.0/15154.244.0.1 to 154.245.255.254154.245.255.255131,070
124154.246.0.0/15154.246.0.1 to 154.247.255.254154.247.255.255131,070
125154.248.0.0/15154.248.0.1 to 154.249.255.254154.249.255.255131,070
126154.250.0.0/15154.250.0.1 to 154.251.255.254154.251.255.255131,070
127154.252.0.0/15154.252.0.1 to 154.253.255.254154.253.255.255131,070
128154.254.0.0/15154.254.0.1 to 154.255.255.254154.255.255.255131,070

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.