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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.

Network238.192.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
238.192.0.0
Broadcast address
238.255.255.255
First usable
238.192.0.1
Last usable
238.255.255.254
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
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex EEC00000 · Integer 4005560320 to 4009754623
Reverse DNS zones
192.238.in-addr.arpa
193.238.in-addr.arpa
194.238.in-addr.arpa
195.238.in-addr.arpa
196.238.in-addr.arpa
197.238.in-addr.arpa
198.238.in-addr.arpa
199.238.in-addr.arpa
200.238.in-addr.arpa
201.238.in-addr.arpa
202.238.in-addr.arpa
203.238.in-addr.arpa
204.238.in-addr.arpa
205.238.in-addr.arpa
206.238.in-addr.arpa
207.238.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
Address11101110.11000000.00000000.00000000238.192.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11101110.11000000.00000000.00000000238.192.0.0
Broadcast11101110.11111111.11111111.11111111238.255.255.255
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)

238.192.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1238.192.0.0/17238.192.0.1 to 238.192.127.254238.192.127.25532,766
2238.192.128.0/17238.192.128.1 to 238.192.255.254238.192.255.25532,766
3238.193.0.0/17238.193.0.1 to 238.193.127.254238.193.127.25532,766
4238.193.128.0/17238.193.128.1 to 238.193.255.254238.193.255.25532,766
5238.194.0.0/17238.194.0.1 to 238.194.127.254238.194.127.25532,766
6238.194.128.0/17238.194.128.1 to 238.194.255.254238.194.255.25532,766
7238.195.0.0/17238.195.0.1 to 238.195.127.254238.195.127.25532,766
8238.195.128.0/17238.195.128.1 to 238.195.255.254238.195.255.25532,766
9238.196.0.0/17238.196.0.1 to 238.196.127.254238.196.127.25532,766
10238.196.128.0/17238.196.128.1 to 238.196.255.254238.196.255.25532,766
11238.197.0.0/17238.197.0.1 to 238.197.127.254238.197.127.25532,766
12238.197.128.0/17238.197.128.1 to 238.197.255.254238.197.255.25532,766
13238.198.0.0/17238.198.0.1 to 238.198.127.254238.198.127.25532,766
14238.198.128.0/17238.198.128.1 to 238.198.255.254238.198.255.25532,766
15238.199.0.0/17238.199.0.1 to 238.199.127.254238.199.127.25532,766
16238.199.128.0/17238.199.128.1 to 238.199.255.254238.199.255.25532,766
17238.200.0.0/17238.200.0.1 to 238.200.127.254238.200.127.25532,766
18238.200.128.0/17238.200.128.1 to 238.200.255.254238.200.255.25532,766
19238.201.0.0/17238.201.0.1 to 238.201.127.254238.201.127.25532,766
20238.201.128.0/17238.201.128.1 to 238.201.255.254238.201.255.25532,766
21238.202.0.0/17238.202.0.1 to 238.202.127.254238.202.127.25532,766
22238.202.128.0/17238.202.128.1 to 238.202.255.254238.202.255.25532,766
23238.203.0.0/17238.203.0.1 to 238.203.127.254238.203.127.25532,766
24238.203.128.0/17238.203.128.1 to 238.203.255.254238.203.255.25532,766
25238.204.0.0/17238.204.0.1 to 238.204.127.254238.204.127.25532,766
26238.204.128.0/17238.204.128.1 to 238.204.255.254238.204.255.25532,766
27238.205.0.0/17238.205.0.1 to 238.205.127.254238.205.127.25532,766
28238.205.128.0/17238.205.128.1 to 238.205.255.254238.205.255.25532,766
29238.206.0.0/17238.206.0.1 to 238.206.127.254238.206.127.25532,766
30238.206.128.0/17238.206.128.1 to 238.206.255.254238.206.255.25532,766
31238.207.0.0/17238.207.0.1 to 238.207.127.254238.207.127.25532,766
32238.207.128.0/17238.207.128.1 to 238.207.255.254238.207.255.25532,766
33238.208.0.0/17238.208.0.1 to 238.208.127.254238.208.127.25532,766
34238.208.128.0/17238.208.128.1 to 238.208.255.254238.208.255.25532,766
35238.209.0.0/17238.209.0.1 to 238.209.127.254238.209.127.25532,766
36238.209.128.0/17238.209.128.1 to 238.209.255.254238.209.255.25532,766
37238.210.0.0/17238.210.0.1 to 238.210.127.254238.210.127.25532,766
38238.210.128.0/17238.210.128.1 to 238.210.255.254238.210.255.25532,766
39238.211.0.0/17238.211.0.1 to 238.211.127.254238.211.127.25532,766
40238.211.128.0/17238.211.128.1 to 238.211.255.254238.211.255.25532,766
41238.212.0.0/17238.212.0.1 to 238.212.127.254238.212.127.25532,766
42238.212.128.0/17238.212.128.1 to 238.212.255.254238.212.255.25532,766
43238.213.0.0/17238.213.0.1 to 238.213.127.254238.213.127.25532,766
44238.213.128.0/17238.213.128.1 to 238.213.255.254238.213.255.25532,766
45238.214.0.0/17238.214.0.1 to 238.214.127.254238.214.127.25532,766
46238.214.128.0/17238.214.128.1 to 238.214.255.254238.214.255.25532,766
47238.215.0.0/17238.215.0.1 to 238.215.127.254238.215.127.25532,766
48238.215.128.0/17238.215.128.1 to 238.215.255.254238.215.255.25532,766
49238.216.0.0/17238.216.0.1 to 238.216.127.254238.216.127.25532,766
50238.216.128.0/17238.216.128.1 to 238.216.255.254238.216.255.25532,766
51238.217.0.0/17238.217.0.1 to 238.217.127.254238.217.127.25532,766
52238.217.128.0/17238.217.128.1 to 238.217.255.254238.217.255.25532,766
53238.218.0.0/17238.218.0.1 to 238.218.127.254238.218.127.25532,766
54238.218.128.0/17238.218.128.1 to 238.218.255.254238.218.255.25532,766
55238.219.0.0/17238.219.0.1 to 238.219.127.254238.219.127.25532,766
56238.219.128.0/17238.219.128.1 to 238.219.255.254238.219.255.25532,766
57238.220.0.0/17238.220.0.1 to 238.220.127.254238.220.127.25532,766
58238.220.128.0/17238.220.128.1 to 238.220.255.254238.220.255.25532,766
59238.221.0.0/17238.221.0.1 to 238.221.127.254238.221.127.25532,766
60238.221.128.0/17238.221.128.1 to 238.221.255.254238.221.255.25532,766
61238.222.0.0/17238.222.0.1 to 238.222.127.254238.222.127.25532,766
62238.222.128.0/17238.222.128.1 to 238.222.255.254238.222.255.25532,766
63238.223.0.0/17238.223.0.1 to 238.223.127.254238.223.127.25532,766
64238.223.128.0/17238.223.128.1 to 238.223.255.254238.223.255.25532,766
65238.224.0.0/17238.224.0.1 to 238.224.127.254238.224.127.25532,766
66238.224.128.0/17238.224.128.1 to 238.224.255.254238.224.255.25532,766
67238.225.0.0/17238.225.0.1 to 238.225.127.254238.225.127.25532,766
68238.225.128.0/17238.225.128.1 to 238.225.255.254238.225.255.25532,766
69238.226.0.0/17238.226.0.1 to 238.226.127.254238.226.127.25532,766
70238.226.128.0/17238.226.128.1 to 238.226.255.254238.226.255.25532,766
71238.227.0.0/17238.227.0.1 to 238.227.127.254238.227.127.25532,766
72238.227.128.0/17238.227.128.1 to 238.227.255.254238.227.255.25532,766
73238.228.0.0/17238.228.0.1 to 238.228.127.254238.228.127.25532,766
74238.228.128.0/17238.228.128.1 to 238.228.255.254238.228.255.25532,766
75238.229.0.0/17238.229.0.1 to 238.229.127.254238.229.127.25532,766
76238.229.128.0/17238.229.128.1 to 238.229.255.254238.229.255.25532,766
77238.230.0.0/17238.230.0.1 to 238.230.127.254238.230.127.25532,766
78238.230.128.0/17238.230.128.1 to 238.230.255.254238.230.255.25532,766
79238.231.0.0/17238.231.0.1 to 238.231.127.254238.231.127.25532,766
80238.231.128.0/17238.231.128.1 to 238.231.255.254238.231.255.25532,766
81238.232.0.0/17238.232.0.1 to 238.232.127.254238.232.127.25532,766
82238.232.128.0/17238.232.128.1 to 238.232.255.254238.232.255.25532,766
83238.233.0.0/17238.233.0.1 to 238.233.127.254238.233.127.25532,766
84238.233.128.0/17238.233.128.1 to 238.233.255.254238.233.255.25532,766
85238.234.0.0/17238.234.0.1 to 238.234.127.254238.234.127.25532,766
86238.234.128.0/17238.234.128.1 to 238.234.255.254238.234.255.25532,766
87238.235.0.0/17238.235.0.1 to 238.235.127.254238.235.127.25532,766
88238.235.128.0/17238.235.128.1 to 238.235.255.254238.235.255.25532,766
89238.236.0.0/17238.236.0.1 to 238.236.127.254238.236.127.25532,766
90238.236.128.0/17238.236.128.1 to 238.236.255.254238.236.255.25532,766
91238.237.0.0/17238.237.0.1 to 238.237.127.254238.237.127.25532,766
92238.237.128.0/17238.237.128.1 to 238.237.255.254238.237.255.25532,766
93238.238.0.0/17238.238.0.1 to 238.238.127.254238.238.127.25532,766
94238.238.128.0/17238.238.128.1 to 238.238.255.254238.238.255.25532,766
95238.239.0.0/17238.239.0.1 to 238.239.127.254238.239.127.25532,766
96238.239.128.0/17238.239.128.1 to 238.239.255.254238.239.255.25532,766
97238.240.0.0/17238.240.0.1 to 238.240.127.254238.240.127.25532,766
98238.240.128.0/17238.240.128.1 to 238.240.255.254238.240.255.25532,766
99238.241.0.0/17238.241.0.1 to 238.241.127.254238.241.127.25532,766
100238.241.128.0/17238.241.128.1 to 238.241.255.254238.241.255.25532,766
101238.242.0.0/17238.242.0.1 to 238.242.127.254238.242.127.25532,766
102238.242.128.0/17238.242.128.1 to 238.242.255.254238.242.255.25532,766
103238.243.0.0/17238.243.0.1 to 238.243.127.254238.243.127.25532,766
104238.243.128.0/17238.243.128.1 to 238.243.255.254238.243.255.25532,766
105238.244.0.0/17238.244.0.1 to 238.244.127.254238.244.127.25532,766
106238.244.128.0/17238.244.128.1 to 238.244.255.254238.244.255.25532,766
107238.245.0.0/17238.245.0.1 to 238.245.127.254238.245.127.25532,766
108238.245.128.0/17238.245.128.1 to 238.245.255.254238.245.255.25532,766
109238.246.0.0/17238.246.0.1 to 238.246.127.254238.246.127.25532,766
110238.246.128.0/17238.246.128.1 to 238.246.255.254238.246.255.25532,766
111238.247.0.0/17238.247.0.1 to 238.247.127.254238.247.127.25532,766
112238.247.128.0/17238.247.128.1 to 238.247.255.254238.247.255.25532,766
113238.248.0.0/17238.248.0.1 to 238.248.127.254238.248.127.25532,766
114238.248.128.0/17238.248.128.1 to 238.248.255.254238.248.255.25532,766
115238.249.0.0/17238.249.0.1 to 238.249.127.254238.249.127.25532,766
116238.249.128.0/17238.249.128.1 to 238.249.255.254238.249.255.25532,766
117238.250.0.0/17238.250.0.1 to 238.250.127.254238.250.127.25532,766
118238.250.128.0/17238.250.128.1 to 238.250.255.254238.250.255.25532,766
119238.251.0.0/17238.251.0.1 to 238.251.127.254238.251.127.25532,766
120238.251.128.0/17238.251.128.1 to 238.251.255.254238.251.255.25532,766
121238.252.0.0/17238.252.0.1 to 238.252.127.254238.252.127.25532,766
122238.252.128.0/17238.252.128.1 to 238.252.255.254238.252.255.25532,766
123238.253.0.0/17238.253.0.1 to 238.253.127.254238.253.127.25532,766
124238.253.128.0/17238.253.128.1 to 238.253.255.254238.253.255.25532,766
125238.254.0.0/17238.254.0.1 to 238.254.127.254238.254.127.25532,766
126238.254.128.0/17238.254.128.1 to 238.254.255.254238.254.255.25532,766
127238.255.0.0/17238.255.0.1 to 238.255.127.254238.255.127.25532,766
128238.255.128.0/17238.255.128.1 to 238.255.255.254238.255.255.25532,766

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.