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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.

Network252.128.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
252.128.0.0
Broadcast address
252.191.255.255
First usable
252.128.0.1
Last usable
252.191.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FC800000 · Integer 4236247040 to 4240441343
Reverse DNS zones
128.252.in-addr.arpa
129.252.in-addr.arpa
130.252.in-addr.arpa
131.252.in-addr.arpa
132.252.in-addr.arpa
133.252.in-addr.arpa
134.252.in-addr.arpa
135.252.in-addr.arpa
136.252.in-addr.arpa
137.252.in-addr.arpa
138.252.in-addr.arpa
139.252.in-addr.arpa
140.252.in-addr.arpa
141.252.in-addr.arpa
142.252.in-addr.arpa
143.252.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111100.10000000.00000000.00000000252.128.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11111100.10000000.00000000.00000000252.128.0.0
Broadcast11111100.10111111.11111111.11111111252.191.255.255
Split into smaller subnets/17
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

252.128.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1252.128.0.0/17252.128.0.1 to 252.128.127.254252.128.127.25532,766
2252.128.128.0/17252.128.128.1 to 252.128.255.254252.128.255.25532,766
3252.129.0.0/17252.129.0.1 to 252.129.127.254252.129.127.25532,766
4252.129.128.0/17252.129.128.1 to 252.129.255.254252.129.255.25532,766
5252.130.0.0/17252.130.0.1 to 252.130.127.254252.130.127.25532,766
6252.130.128.0/17252.130.128.1 to 252.130.255.254252.130.255.25532,766
7252.131.0.0/17252.131.0.1 to 252.131.127.254252.131.127.25532,766
8252.131.128.0/17252.131.128.1 to 252.131.255.254252.131.255.25532,766
9252.132.0.0/17252.132.0.1 to 252.132.127.254252.132.127.25532,766
10252.132.128.0/17252.132.128.1 to 252.132.255.254252.132.255.25532,766
11252.133.0.0/17252.133.0.1 to 252.133.127.254252.133.127.25532,766
12252.133.128.0/17252.133.128.1 to 252.133.255.254252.133.255.25532,766
13252.134.0.0/17252.134.0.1 to 252.134.127.254252.134.127.25532,766
14252.134.128.0/17252.134.128.1 to 252.134.255.254252.134.255.25532,766
15252.135.0.0/17252.135.0.1 to 252.135.127.254252.135.127.25532,766
16252.135.128.0/17252.135.128.1 to 252.135.255.254252.135.255.25532,766
17252.136.0.0/17252.136.0.1 to 252.136.127.254252.136.127.25532,766
18252.136.128.0/17252.136.128.1 to 252.136.255.254252.136.255.25532,766
19252.137.0.0/17252.137.0.1 to 252.137.127.254252.137.127.25532,766
20252.137.128.0/17252.137.128.1 to 252.137.255.254252.137.255.25532,766
21252.138.0.0/17252.138.0.1 to 252.138.127.254252.138.127.25532,766
22252.138.128.0/17252.138.128.1 to 252.138.255.254252.138.255.25532,766
23252.139.0.0/17252.139.0.1 to 252.139.127.254252.139.127.25532,766
24252.139.128.0/17252.139.128.1 to 252.139.255.254252.139.255.25532,766
25252.140.0.0/17252.140.0.1 to 252.140.127.254252.140.127.25532,766
26252.140.128.0/17252.140.128.1 to 252.140.255.254252.140.255.25532,766
27252.141.0.0/17252.141.0.1 to 252.141.127.254252.141.127.25532,766
28252.141.128.0/17252.141.128.1 to 252.141.255.254252.141.255.25532,766
29252.142.0.0/17252.142.0.1 to 252.142.127.254252.142.127.25532,766
30252.142.128.0/17252.142.128.1 to 252.142.255.254252.142.255.25532,766
31252.143.0.0/17252.143.0.1 to 252.143.127.254252.143.127.25532,766
32252.143.128.0/17252.143.128.1 to 252.143.255.254252.143.255.25532,766
33252.144.0.0/17252.144.0.1 to 252.144.127.254252.144.127.25532,766
34252.144.128.0/17252.144.128.1 to 252.144.255.254252.144.255.25532,766
35252.145.0.0/17252.145.0.1 to 252.145.127.254252.145.127.25532,766
36252.145.128.0/17252.145.128.1 to 252.145.255.254252.145.255.25532,766
37252.146.0.0/17252.146.0.1 to 252.146.127.254252.146.127.25532,766
38252.146.128.0/17252.146.128.1 to 252.146.255.254252.146.255.25532,766
39252.147.0.0/17252.147.0.1 to 252.147.127.254252.147.127.25532,766
40252.147.128.0/17252.147.128.1 to 252.147.255.254252.147.255.25532,766
41252.148.0.0/17252.148.0.1 to 252.148.127.254252.148.127.25532,766
42252.148.128.0/17252.148.128.1 to 252.148.255.254252.148.255.25532,766
43252.149.0.0/17252.149.0.1 to 252.149.127.254252.149.127.25532,766
44252.149.128.0/17252.149.128.1 to 252.149.255.254252.149.255.25532,766
45252.150.0.0/17252.150.0.1 to 252.150.127.254252.150.127.25532,766
46252.150.128.0/17252.150.128.1 to 252.150.255.254252.150.255.25532,766
47252.151.0.0/17252.151.0.1 to 252.151.127.254252.151.127.25532,766
48252.151.128.0/17252.151.128.1 to 252.151.255.254252.151.255.25532,766
49252.152.0.0/17252.152.0.1 to 252.152.127.254252.152.127.25532,766
50252.152.128.0/17252.152.128.1 to 252.152.255.254252.152.255.25532,766
51252.153.0.0/17252.153.0.1 to 252.153.127.254252.153.127.25532,766
52252.153.128.0/17252.153.128.1 to 252.153.255.254252.153.255.25532,766
53252.154.0.0/17252.154.0.1 to 252.154.127.254252.154.127.25532,766
54252.154.128.0/17252.154.128.1 to 252.154.255.254252.154.255.25532,766
55252.155.0.0/17252.155.0.1 to 252.155.127.254252.155.127.25532,766
56252.155.128.0/17252.155.128.1 to 252.155.255.254252.155.255.25532,766
57252.156.0.0/17252.156.0.1 to 252.156.127.254252.156.127.25532,766
58252.156.128.0/17252.156.128.1 to 252.156.255.254252.156.255.25532,766
59252.157.0.0/17252.157.0.1 to 252.157.127.254252.157.127.25532,766
60252.157.128.0/17252.157.128.1 to 252.157.255.254252.157.255.25532,766
61252.158.0.0/17252.158.0.1 to 252.158.127.254252.158.127.25532,766
62252.158.128.0/17252.158.128.1 to 252.158.255.254252.158.255.25532,766
63252.159.0.0/17252.159.0.1 to 252.159.127.254252.159.127.25532,766
64252.159.128.0/17252.159.128.1 to 252.159.255.254252.159.255.25532,766
65252.160.0.0/17252.160.0.1 to 252.160.127.254252.160.127.25532,766
66252.160.128.0/17252.160.128.1 to 252.160.255.254252.160.255.25532,766
67252.161.0.0/17252.161.0.1 to 252.161.127.254252.161.127.25532,766
68252.161.128.0/17252.161.128.1 to 252.161.255.254252.161.255.25532,766
69252.162.0.0/17252.162.0.1 to 252.162.127.254252.162.127.25532,766
70252.162.128.0/17252.162.128.1 to 252.162.255.254252.162.255.25532,766
71252.163.0.0/17252.163.0.1 to 252.163.127.254252.163.127.25532,766
72252.163.128.0/17252.163.128.1 to 252.163.255.254252.163.255.25532,766
73252.164.0.0/17252.164.0.1 to 252.164.127.254252.164.127.25532,766
74252.164.128.0/17252.164.128.1 to 252.164.255.254252.164.255.25532,766
75252.165.0.0/17252.165.0.1 to 252.165.127.254252.165.127.25532,766
76252.165.128.0/17252.165.128.1 to 252.165.255.254252.165.255.25532,766
77252.166.0.0/17252.166.0.1 to 252.166.127.254252.166.127.25532,766
78252.166.128.0/17252.166.128.1 to 252.166.255.254252.166.255.25532,766
79252.167.0.0/17252.167.0.1 to 252.167.127.254252.167.127.25532,766
80252.167.128.0/17252.167.128.1 to 252.167.255.254252.167.255.25532,766
81252.168.0.0/17252.168.0.1 to 252.168.127.254252.168.127.25532,766
82252.168.128.0/17252.168.128.1 to 252.168.255.254252.168.255.25532,766
83252.169.0.0/17252.169.0.1 to 252.169.127.254252.169.127.25532,766
84252.169.128.0/17252.169.128.1 to 252.169.255.254252.169.255.25532,766
85252.170.0.0/17252.170.0.1 to 252.170.127.254252.170.127.25532,766
86252.170.128.0/17252.170.128.1 to 252.170.255.254252.170.255.25532,766
87252.171.0.0/17252.171.0.1 to 252.171.127.254252.171.127.25532,766
88252.171.128.0/17252.171.128.1 to 252.171.255.254252.171.255.25532,766
89252.172.0.0/17252.172.0.1 to 252.172.127.254252.172.127.25532,766
90252.172.128.0/17252.172.128.1 to 252.172.255.254252.172.255.25532,766
91252.173.0.0/17252.173.0.1 to 252.173.127.254252.173.127.25532,766
92252.173.128.0/17252.173.128.1 to 252.173.255.254252.173.255.25532,766
93252.174.0.0/17252.174.0.1 to 252.174.127.254252.174.127.25532,766
94252.174.128.0/17252.174.128.1 to 252.174.255.254252.174.255.25532,766
95252.175.0.0/17252.175.0.1 to 252.175.127.254252.175.127.25532,766
96252.175.128.0/17252.175.128.1 to 252.175.255.254252.175.255.25532,766
97252.176.0.0/17252.176.0.1 to 252.176.127.254252.176.127.25532,766
98252.176.128.0/17252.176.128.1 to 252.176.255.254252.176.255.25532,766
99252.177.0.0/17252.177.0.1 to 252.177.127.254252.177.127.25532,766
100252.177.128.0/17252.177.128.1 to 252.177.255.254252.177.255.25532,766
101252.178.0.0/17252.178.0.1 to 252.178.127.254252.178.127.25532,766
102252.178.128.0/17252.178.128.1 to 252.178.255.254252.178.255.25532,766
103252.179.0.0/17252.179.0.1 to 252.179.127.254252.179.127.25532,766
104252.179.128.0/17252.179.128.1 to 252.179.255.254252.179.255.25532,766
105252.180.0.0/17252.180.0.1 to 252.180.127.254252.180.127.25532,766
106252.180.128.0/17252.180.128.1 to 252.180.255.254252.180.255.25532,766
107252.181.0.0/17252.181.0.1 to 252.181.127.254252.181.127.25532,766
108252.181.128.0/17252.181.128.1 to 252.181.255.254252.181.255.25532,766
109252.182.0.0/17252.182.0.1 to 252.182.127.254252.182.127.25532,766
110252.182.128.0/17252.182.128.1 to 252.182.255.254252.182.255.25532,766
111252.183.0.0/17252.183.0.1 to 252.183.127.254252.183.127.25532,766
112252.183.128.0/17252.183.128.1 to 252.183.255.254252.183.255.25532,766
113252.184.0.0/17252.184.0.1 to 252.184.127.254252.184.127.25532,766
114252.184.128.0/17252.184.128.1 to 252.184.255.254252.184.255.25532,766
115252.185.0.0/17252.185.0.1 to 252.185.127.254252.185.127.25532,766
116252.185.128.0/17252.185.128.1 to 252.185.255.254252.185.255.25532,766
117252.186.0.0/17252.186.0.1 to 252.186.127.254252.186.127.25532,766
118252.186.128.0/17252.186.128.1 to 252.186.255.254252.186.255.25532,766
119252.187.0.0/17252.187.0.1 to 252.187.127.254252.187.127.25532,766
120252.187.128.0/17252.187.128.1 to 252.187.255.254252.187.255.25532,766
121252.188.0.0/17252.188.0.1 to 252.188.127.254252.188.127.25532,766
122252.188.128.0/17252.188.128.1 to 252.188.255.254252.188.255.25532,766
123252.189.0.0/17252.189.0.1 to 252.189.127.254252.189.127.25532,766
124252.189.128.0/17252.189.128.1 to 252.189.255.254252.189.255.25532,766
125252.190.0.0/17252.190.0.1 to 252.190.127.254252.190.127.25532,766
126252.190.128.0/17252.190.128.1 to 252.190.255.254252.190.255.25532,766
127252.191.0.0/17252.191.0.1 to 252.191.127.254252.191.127.25532,766
128252.191.128.0/17252.191.128.1 to 252.191.255.254252.191.255.25532,766

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.