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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.

Network254.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
254.0.0.0
Broadcast address
254.255.255.255
First usable
254.0.0.1
Last usable
254.255.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FE000000 · Integer 4261412864 to 4278190079
Reverse DNS zone
254.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111110..00000000.00000000.00000000254.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network11111110..00000000.00000000.00000000254.0.0.0
Broadcast11111110..11111111.11111111.11111111254.255.255.255
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)

254.0.0.0/8 makes 128 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1254.0.0.0/15254.0.0.1 to 254.1.255.254254.1.255.255131,070
2254.2.0.0/15254.2.0.1 to 254.3.255.254254.3.255.255131,070
3254.4.0.0/15254.4.0.1 to 254.5.255.254254.5.255.255131,070
4254.6.0.0/15254.6.0.1 to 254.7.255.254254.7.255.255131,070
5254.8.0.0/15254.8.0.1 to 254.9.255.254254.9.255.255131,070
6254.10.0.0/15254.10.0.1 to 254.11.255.254254.11.255.255131,070
7254.12.0.0/15254.12.0.1 to 254.13.255.254254.13.255.255131,070
8254.14.0.0/15254.14.0.1 to 254.15.255.254254.15.255.255131,070
9254.16.0.0/15254.16.0.1 to 254.17.255.254254.17.255.255131,070
10254.18.0.0/15254.18.0.1 to 254.19.255.254254.19.255.255131,070
11254.20.0.0/15254.20.0.1 to 254.21.255.254254.21.255.255131,070
12254.22.0.0/15254.22.0.1 to 254.23.255.254254.23.255.255131,070
13254.24.0.0/15254.24.0.1 to 254.25.255.254254.25.255.255131,070
14254.26.0.0/15254.26.0.1 to 254.27.255.254254.27.255.255131,070
15254.28.0.0/15254.28.0.1 to 254.29.255.254254.29.255.255131,070
16254.30.0.0/15254.30.0.1 to 254.31.255.254254.31.255.255131,070
17254.32.0.0/15254.32.0.1 to 254.33.255.254254.33.255.255131,070
18254.34.0.0/15254.34.0.1 to 254.35.255.254254.35.255.255131,070
19254.36.0.0/15254.36.0.1 to 254.37.255.254254.37.255.255131,070
20254.38.0.0/15254.38.0.1 to 254.39.255.254254.39.255.255131,070
21254.40.0.0/15254.40.0.1 to 254.41.255.254254.41.255.255131,070
22254.42.0.0/15254.42.0.1 to 254.43.255.254254.43.255.255131,070
23254.44.0.0/15254.44.0.1 to 254.45.255.254254.45.255.255131,070
24254.46.0.0/15254.46.0.1 to 254.47.255.254254.47.255.255131,070
25254.48.0.0/15254.48.0.1 to 254.49.255.254254.49.255.255131,070
26254.50.0.0/15254.50.0.1 to 254.51.255.254254.51.255.255131,070
27254.52.0.0/15254.52.0.1 to 254.53.255.254254.53.255.255131,070
28254.54.0.0/15254.54.0.1 to 254.55.255.254254.55.255.255131,070
29254.56.0.0/15254.56.0.1 to 254.57.255.254254.57.255.255131,070
30254.58.0.0/15254.58.0.1 to 254.59.255.254254.59.255.255131,070
31254.60.0.0/15254.60.0.1 to 254.61.255.254254.61.255.255131,070
32254.62.0.0/15254.62.0.1 to 254.63.255.254254.63.255.255131,070
33254.64.0.0/15254.64.0.1 to 254.65.255.254254.65.255.255131,070
34254.66.0.0/15254.66.0.1 to 254.67.255.254254.67.255.255131,070
35254.68.0.0/15254.68.0.1 to 254.69.255.254254.69.255.255131,070
36254.70.0.0/15254.70.0.1 to 254.71.255.254254.71.255.255131,070
37254.72.0.0/15254.72.0.1 to 254.73.255.254254.73.255.255131,070
38254.74.0.0/15254.74.0.1 to 254.75.255.254254.75.255.255131,070
39254.76.0.0/15254.76.0.1 to 254.77.255.254254.77.255.255131,070
40254.78.0.0/15254.78.0.1 to 254.79.255.254254.79.255.255131,070
41254.80.0.0/15254.80.0.1 to 254.81.255.254254.81.255.255131,070
42254.82.0.0/15254.82.0.1 to 254.83.255.254254.83.255.255131,070
43254.84.0.0/15254.84.0.1 to 254.85.255.254254.85.255.255131,070
44254.86.0.0/15254.86.0.1 to 254.87.255.254254.87.255.255131,070
45254.88.0.0/15254.88.0.1 to 254.89.255.254254.89.255.255131,070
46254.90.0.0/15254.90.0.1 to 254.91.255.254254.91.255.255131,070
47254.92.0.0/15254.92.0.1 to 254.93.255.254254.93.255.255131,070
48254.94.0.0/15254.94.0.1 to 254.95.255.254254.95.255.255131,070
49254.96.0.0/15254.96.0.1 to 254.97.255.254254.97.255.255131,070
50254.98.0.0/15254.98.0.1 to 254.99.255.254254.99.255.255131,070
51254.100.0.0/15254.100.0.1 to 254.101.255.254254.101.255.255131,070
52254.102.0.0/15254.102.0.1 to 254.103.255.254254.103.255.255131,070
53254.104.0.0/15254.104.0.1 to 254.105.255.254254.105.255.255131,070
54254.106.0.0/15254.106.0.1 to 254.107.255.254254.107.255.255131,070
55254.108.0.0/15254.108.0.1 to 254.109.255.254254.109.255.255131,070
56254.110.0.0/15254.110.0.1 to 254.111.255.254254.111.255.255131,070
57254.112.0.0/15254.112.0.1 to 254.113.255.254254.113.255.255131,070
58254.114.0.0/15254.114.0.1 to 254.115.255.254254.115.255.255131,070
59254.116.0.0/15254.116.0.1 to 254.117.255.254254.117.255.255131,070
60254.118.0.0/15254.118.0.1 to 254.119.255.254254.119.255.255131,070
61254.120.0.0/15254.120.0.1 to 254.121.255.254254.121.255.255131,070
62254.122.0.0/15254.122.0.1 to 254.123.255.254254.123.255.255131,070
63254.124.0.0/15254.124.0.1 to 254.125.255.254254.125.255.255131,070
64254.126.0.0/15254.126.0.1 to 254.127.255.254254.127.255.255131,070
65254.128.0.0/15254.128.0.1 to 254.129.255.254254.129.255.255131,070
66254.130.0.0/15254.130.0.1 to 254.131.255.254254.131.255.255131,070
67254.132.0.0/15254.132.0.1 to 254.133.255.254254.133.255.255131,070
68254.134.0.0/15254.134.0.1 to 254.135.255.254254.135.255.255131,070
69254.136.0.0/15254.136.0.1 to 254.137.255.254254.137.255.255131,070
70254.138.0.0/15254.138.0.1 to 254.139.255.254254.139.255.255131,070
71254.140.0.0/15254.140.0.1 to 254.141.255.254254.141.255.255131,070
72254.142.0.0/15254.142.0.1 to 254.143.255.254254.143.255.255131,070
73254.144.0.0/15254.144.0.1 to 254.145.255.254254.145.255.255131,070
74254.146.0.0/15254.146.0.1 to 254.147.255.254254.147.255.255131,070
75254.148.0.0/15254.148.0.1 to 254.149.255.254254.149.255.255131,070
76254.150.0.0/15254.150.0.1 to 254.151.255.254254.151.255.255131,070
77254.152.0.0/15254.152.0.1 to 254.153.255.254254.153.255.255131,070
78254.154.0.0/15254.154.0.1 to 254.155.255.254254.155.255.255131,070
79254.156.0.0/15254.156.0.1 to 254.157.255.254254.157.255.255131,070
80254.158.0.0/15254.158.0.1 to 254.159.255.254254.159.255.255131,070
81254.160.0.0/15254.160.0.1 to 254.161.255.254254.161.255.255131,070
82254.162.0.0/15254.162.0.1 to 254.163.255.254254.163.255.255131,070
83254.164.0.0/15254.164.0.1 to 254.165.255.254254.165.255.255131,070
84254.166.0.0/15254.166.0.1 to 254.167.255.254254.167.255.255131,070
85254.168.0.0/15254.168.0.1 to 254.169.255.254254.169.255.255131,070
86254.170.0.0/15254.170.0.1 to 254.171.255.254254.171.255.255131,070
87254.172.0.0/15254.172.0.1 to 254.173.255.254254.173.255.255131,070
88254.174.0.0/15254.174.0.1 to 254.175.255.254254.175.255.255131,070
89254.176.0.0/15254.176.0.1 to 254.177.255.254254.177.255.255131,070
90254.178.0.0/15254.178.0.1 to 254.179.255.254254.179.255.255131,070
91254.180.0.0/15254.180.0.1 to 254.181.255.254254.181.255.255131,070
92254.182.0.0/15254.182.0.1 to 254.183.255.254254.183.255.255131,070
93254.184.0.0/15254.184.0.1 to 254.185.255.254254.185.255.255131,070
94254.186.0.0/15254.186.0.1 to 254.187.255.254254.187.255.255131,070
95254.188.0.0/15254.188.0.1 to 254.189.255.254254.189.255.255131,070
96254.190.0.0/15254.190.0.1 to 254.191.255.254254.191.255.255131,070
97254.192.0.0/15254.192.0.1 to 254.193.255.254254.193.255.255131,070
98254.194.0.0/15254.194.0.1 to 254.195.255.254254.195.255.255131,070
99254.196.0.0/15254.196.0.1 to 254.197.255.254254.197.255.255131,070
100254.198.0.0/15254.198.0.1 to 254.199.255.254254.199.255.255131,070
101254.200.0.0/15254.200.0.1 to 254.201.255.254254.201.255.255131,070
102254.202.0.0/15254.202.0.1 to 254.203.255.254254.203.255.255131,070
103254.204.0.0/15254.204.0.1 to 254.205.255.254254.205.255.255131,070
104254.206.0.0/15254.206.0.1 to 254.207.255.254254.207.255.255131,070
105254.208.0.0/15254.208.0.1 to 254.209.255.254254.209.255.255131,070
106254.210.0.0/15254.210.0.1 to 254.211.255.254254.211.255.255131,070
107254.212.0.0/15254.212.0.1 to 254.213.255.254254.213.255.255131,070
108254.214.0.0/15254.214.0.1 to 254.215.255.254254.215.255.255131,070
109254.216.0.0/15254.216.0.1 to 254.217.255.254254.217.255.255131,070
110254.218.0.0/15254.218.0.1 to 254.219.255.254254.219.255.255131,070
111254.220.0.0/15254.220.0.1 to 254.221.255.254254.221.255.255131,070
112254.222.0.0/15254.222.0.1 to 254.223.255.254254.223.255.255131,070
113254.224.0.0/15254.224.0.1 to 254.225.255.254254.225.255.255131,070
114254.226.0.0/15254.226.0.1 to 254.227.255.254254.227.255.255131,070
115254.228.0.0/15254.228.0.1 to 254.229.255.254254.229.255.255131,070
116254.230.0.0/15254.230.0.1 to 254.231.255.254254.231.255.255131,070
117254.232.0.0/15254.232.0.1 to 254.233.255.254254.233.255.255131,070
118254.234.0.0/15254.234.0.1 to 254.235.255.254254.235.255.255131,070
119254.236.0.0/15254.236.0.1 to 254.237.255.254254.237.255.255131,070
120254.238.0.0/15254.238.0.1 to 254.239.255.254254.239.255.255131,070
121254.240.0.0/15254.240.0.1 to 254.241.255.254254.241.255.255131,070
122254.242.0.0/15254.242.0.1 to 254.243.255.254254.243.255.255131,070
123254.244.0.0/15254.244.0.1 to 254.245.255.254254.245.255.255131,070
124254.246.0.0/15254.246.0.1 to 254.247.255.254254.247.255.255131,070
125254.248.0.0/15254.248.0.1 to 254.249.255.254254.249.255.255131,070
126254.250.0.0/15254.250.0.1 to 254.251.255.254254.251.255.255131,070
127254.252.0.0/15254.252.0.1 to 254.253.255.254254.253.255.255131,070
128254.254.0.0/15254.254.0.1 to 254.255.255.254254.255.255.255131,070

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.