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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.

Network252.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
252.0.0.0
Broadcast address
253.255.255.255
First usable
252.0.0.1
Last usable
253.255.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FC000000 · Integer 4227858432 to 4261412863
Reverse DNS zones
252.in-addr.arpa
253.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
Address11111100.00000000.00000000.00000000252.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network11111100.00000000.00000000.00000000252.0.0.0
Broadcast11111101.11111111.11111111.11111111253.255.255.255
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)

252.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1252.0.0.0/14252.0.0.1 to 252.3.255.254252.3.255.255262,142
2252.4.0.0/14252.4.0.1 to 252.7.255.254252.7.255.255262,142
3252.8.0.0/14252.8.0.1 to 252.11.255.254252.11.255.255262,142
4252.12.0.0/14252.12.0.1 to 252.15.255.254252.15.255.255262,142
5252.16.0.0/14252.16.0.1 to 252.19.255.254252.19.255.255262,142
6252.20.0.0/14252.20.0.1 to 252.23.255.254252.23.255.255262,142
7252.24.0.0/14252.24.0.1 to 252.27.255.254252.27.255.255262,142
8252.28.0.0/14252.28.0.1 to 252.31.255.254252.31.255.255262,142
9252.32.0.0/14252.32.0.1 to 252.35.255.254252.35.255.255262,142
10252.36.0.0/14252.36.0.1 to 252.39.255.254252.39.255.255262,142
11252.40.0.0/14252.40.0.1 to 252.43.255.254252.43.255.255262,142
12252.44.0.0/14252.44.0.1 to 252.47.255.254252.47.255.255262,142
13252.48.0.0/14252.48.0.1 to 252.51.255.254252.51.255.255262,142
14252.52.0.0/14252.52.0.1 to 252.55.255.254252.55.255.255262,142
15252.56.0.0/14252.56.0.1 to 252.59.255.254252.59.255.255262,142
16252.60.0.0/14252.60.0.1 to 252.63.255.254252.63.255.255262,142
17252.64.0.0/14252.64.0.1 to 252.67.255.254252.67.255.255262,142
18252.68.0.0/14252.68.0.1 to 252.71.255.254252.71.255.255262,142
19252.72.0.0/14252.72.0.1 to 252.75.255.254252.75.255.255262,142
20252.76.0.0/14252.76.0.1 to 252.79.255.254252.79.255.255262,142
21252.80.0.0/14252.80.0.1 to 252.83.255.254252.83.255.255262,142
22252.84.0.0/14252.84.0.1 to 252.87.255.254252.87.255.255262,142
23252.88.0.0/14252.88.0.1 to 252.91.255.254252.91.255.255262,142
24252.92.0.0/14252.92.0.1 to 252.95.255.254252.95.255.255262,142
25252.96.0.0/14252.96.0.1 to 252.99.255.254252.99.255.255262,142
26252.100.0.0/14252.100.0.1 to 252.103.255.254252.103.255.255262,142
27252.104.0.0/14252.104.0.1 to 252.107.255.254252.107.255.255262,142
28252.108.0.0/14252.108.0.1 to 252.111.255.254252.111.255.255262,142
29252.112.0.0/14252.112.0.1 to 252.115.255.254252.115.255.255262,142
30252.116.0.0/14252.116.0.1 to 252.119.255.254252.119.255.255262,142
31252.120.0.0/14252.120.0.1 to 252.123.255.254252.123.255.255262,142
32252.124.0.0/14252.124.0.1 to 252.127.255.254252.127.255.255262,142
33252.128.0.0/14252.128.0.1 to 252.131.255.254252.131.255.255262,142
34252.132.0.0/14252.132.0.1 to 252.135.255.254252.135.255.255262,142
35252.136.0.0/14252.136.0.1 to 252.139.255.254252.139.255.255262,142
36252.140.0.0/14252.140.0.1 to 252.143.255.254252.143.255.255262,142
37252.144.0.0/14252.144.0.1 to 252.147.255.254252.147.255.255262,142
38252.148.0.0/14252.148.0.1 to 252.151.255.254252.151.255.255262,142
39252.152.0.0/14252.152.0.1 to 252.155.255.254252.155.255.255262,142
40252.156.0.0/14252.156.0.1 to 252.159.255.254252.159.255.255262,142
41252.160.0.0/14252.160.0.1 to 252.163.255.254252.163.255.255262,142
42252.164.0.0/14252.164.0.1 to 252.167.255.254252.167.255.255262,142
43252.168.0.0/14252.168.0.1 to 252.171.255.254252.171.255.255262,142
44252.172.0.0/14252.172.0.1 to 252.175.255.254252.175.255.255262,142
45252.176.0.0/14252.176.0.1 to 252.179.255.254252.179.255.255262,142
46252.180.0.0/14252.180.0.1 to 252.183.255.254252.183.255.255262,142
47252.184.0.0/14252.184.0.1 to 252.187.255.254252.187.255.255262,142
48252.188.0.0/14252.188.0.1 to 252.191.255.254252.191.255.255262,142
49252.192.0.0/14252.192.0.1 to 252.195.255.254252.195.255.255262,142
50252.196.0.0/14252.196.0.1 to 252.199.255.254252.199.255.255262,142
51252.200.0.0/14252.200.0.1 to 252.203.255.254252.203.255.255262,142
52252.204.0.0/14252.204.0.1 to 252.207.255.254252.207.255.255262,142
53252.208.0.0/14252.208.0.1 to 252.211.255.254252.211.255.255262,142
54252.212.0.0/14252.212.0.1 to 252.215.255.254252.215.255.255262,142
55252.216.0.0/14252.216.0.1 to 252.219.255.254252.219.255.255262,142
56252.220.0.0/14252.220.0.1 to 252.223.255.254252.223.255.255262,142
57252.224.0.0/14252.224.0.1 to 252.227.255.254252.227.255.255262,142
58252.228.0.0/14252.228.0.1 to 252.231.255.254252.231.255.255262,142
59252.232.0.0/14252.232.0.1 to 252.235.255.254252.235.255.255262,142
60252.236.0.0/14252.236.0.1 to 252.239.255.254252.239.255.255262,142
61252.240.0.0/14252.240.0.1 to 252.243.255.254252.243.255.255262,142
62252.244.0.0/14252.244.0.1 to 252.247.255.254252.247.255.255262,142
63252.248.0.0/14252.248.0.1 to 252.251.255.254252.251.255.255262,142
64252.252.0.0/14252.252.0.1 to 252.255.255.254252.255.255.255262,142
65253.0.0.0/14253.0.0.1 to 253.3.255.254253.3.255.255262,142
66253.4.0.0/14253.4.0.1 to 253.7.255.254253.7.255.255262,142
67253.8.0.0/14253.8.0.1 to 253.11.255.254253.11.255.255262,142
68253.12.0.0/14253.12.0.1 to 253.15.255.254253.15.255.255262,142
69253.16.0.0/14253.16.0.1 to 253.19.255.254253.19.255.255262,142
70253.20.0.0/14253.20.0.1 to 253.23.255.254253.23.255.255262,142
71253.24.0.0/14253.24.0.1 to 253.27.255.254253.27.255.255262,142
72253.28.0.0/14253.28.0.1 to 253.31.255.254253.31.255.255262,142
73253.32.0.0/14253.32.0.1 to 253.35.255.254253.35.255.255262,142
74253.36.0.0/14253.36.0.1 to 253.39.255.254253.39.255.255262,142
75253.40.0.0/14253.40.0.1 to 253.43.255.254253.43.255.255262,142
76253.44.0.0/14253.44.0.1 to 253.47.255.254253.47.255.255262,142
77253.48.0.0/14253.48.0.1 to 253.51.255.254253.51.255.255262,142
78253.52.0.0/14253.52.0.1 to 253.55.255.254253.55.255.255262,142
79253.56.0.0/14253.56.0.1 to 253.59.255.254253.59.255.255262,142
80253.60.0.0/14253.60.0.1 to 253.63.255.254253.63.255.255262,142
81253.64.0.0/14253.64.0.1 to 253.67.255.254253.67.255.255262,142
82253.68.0.0/14253.68.0.1 to 253.71.255.254253.71.255.255262,142
83253.72.0.0/14253.72.0.1 to 253.75.255.254253.75.255.255262,142
84253.76.0.0/14253.76.0.1 to 253.79.255.254253.79.255.255262,142
85253.80.0.0/14253.80.0.1 to 253.83.255.254253.83.255.255262,142
86253.84.0.0/14253.84.0.1 to 253.87.255.254253.87.255.255262,142
87253.88.0.0/14253.88.0.1 to 253.91.255.254253.91.255.255262,142
88253.92.0.0/14253.92.0.1 to 253.95.255.254253.95.255.255262,142
89253.96.0.0/14253.96.0.1 to 253.99.255.254253.99.255.255262,142
90253.100.0.0/14253.100.0.1 to 253.103.255.254253.103.255.255262,142
91253.104.0.0/14253.104.0.1 to 253.107.255.254253.107.255.255262,142
92253.108.0.0/14253.108.0.1 to 253.111.255.254253.111.255.255262,142
93253.112.0.0/14253.112.0.1 to 253.115.255.254253.115.255.255262,142
94253.116.0.0/14253.116.0.1 to 253.119.255.254253.119.255.255262,142
95253.120.0.0/14253.120.0.1 to 253.123.255.254253.123.255.255262,142
96253.124.0.0/14253.124.0.1 to 253.127.255.254253.127.255.255262,142
97253.128.0.0/14253.128.0.1 to 253.131.255.254253.131.255.255262,142
98253.132.0.0/14253.132.0.1 to 253.135.255.254253.135.255.255262,142
99253.136.0.0/14253.136.0.1 to 253.139.255.254253.139.255.255262,142
100253.140.0.0/14253.140.0.1 to 253.143.255.254253.143.255.255262,142
101253.144.0.0/14253.144.0.1 to 253.147.255.254253.147.255.255262,142
102253.148.0.0/14253.148.0.1 to 253.151.255.254253.151.255.255262,142
103253.152.0.0/14253.152.0.1 to 253.155.255.254253.155.255.255262,142
104253.156.0.0/14253.156.0.1 to 253.159.255.254253.159.255.255262,142
105253.160.0.0/14253.160.0.1 to 253.163.255.254253.163.255.255262,142
106253.164.0.0/14253.164.0.1 to 253.167.255.254253.167.255.255262,142
107253.168.0.0/14253.168.0.1 to 253.171.255.254253.171.255.255262,142
108253.172.0.0/14253.172.0.1 to 253.175.255.254253.175.255.255262,142
109253.176.0.0/14253.176.0.1 to 253.179.255.254253.179.255.255262,142
110253.180.0.0/14253.180.0.1 to 253.183.255.254253.183.255.255262,142
111253.184.0.0/14253.184.0.1 to 253.187.255.254253.187.255.255262,142
112253.188.0.0/14253.188.0.1 to 253.191.255.254253.191.255.255262,142
113253.192.0.0/14253.192.0.1 to 253.195.255.254253.195.255.255262,142
114253.196.0.0/14253.196.0.1 to 253.199.255.254253.199.255.255262,142
115253.200.0.0/14253.200.0.1 to 253.203.255.254253.203.255.255262,142
116253.204.0.0/14253.204.0.1 to 253.207.255.254253.207.255.255262,142
117253.208.0.0/14253.208.0.1 to 253.211.255.254253.211.255.255262,142
118253.212.0.0/14253.212.0.1 to 253.215.255.254253.215.255.255262,142
119253.216.0.0/14253.216.0.1 to 253.219.255.254253.219.255.255262,142
120253.220.0.0/14253.220.0.1 to 253.223.255.254253.223.255.255262,142
121253.224.0.0/14253.224.0.1 to 253.227.255.254253.227.255.255262,142
122253.228.0.0/14253.228.0.1 to 253.231.255.254253.231.255.255262,142
123253.232.0.0/14253.232.0.1 to 253.235.255.254253.235.255.255262,142
124253.236.0.0/14253.236.0.1 to 253.239.255.254253.239.255.255262,142
125253.240.0.0/14253.240.0.1 to 253.243.255.254253.243.255.255262,142
126253.244.0.0/14253.244.0.1 to 253.247.255.254253.247.255.255262,142
127253.248.0.0/14253.248.0.1 to 253.251.255.254253.251.255.255262,142
128253.252.0.0/14253.252.0.1 to 253.255.255.254253.255.255.255262,142

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.