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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.

Network158.192.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
158.192.0.0
Broadcast address
158.255.255.255
First usable
158.192.0.1
Last usable
158.255.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex 9EC00000 · Integer 2663383040 to 2667577343
Reverse DNS zones
192.158.in-addr.arpa
193.158.in-addr.arpa
194.158.in-addr.arpa
195.158.in-addr.arpa
196.158.in-addr.arpa
197.158.in-addr.arpa
198.158.in-addr.arpa
199.158.in-addr.arpa
200.158.in-addr.arpa
201.158.in-addr.arpa
202.158.in-addr.arpa
203.158.in-addr.arpa
204.158.in-addr.arpa
205.158.in-addr.arpa
206.158.in-addr.arpa
207.158.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
Address10011110.11000000.00000000.00000000158.192.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network10011110.11000000.00000000.00000000158.192.0.0
Broadcast10011110.11111111.11111111.11111111158.255.255.255
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)

158.192.0.0/10 makes 128 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1158.192.0.0/17158.192.0.1 to 158.192.127.254158.192.127.25532,766
2158.192.128.0/17158.192.128.1 to 158.192.255.254158.192.255.25532,766
3158.193.0.0/17158.193.0.1 to 158.193.127.254158.193.127.25532,766
4158.193.128.0/17158.193.128.1 to 158.193.255.254158.193.255.25532,766
5158.194.0.0/17158.194.0.1 to 158.194.127.254158.194.127.25532,766
6158.194.128.0/17158.194.128.1 to 158.194.255.254158.194.255.25532,766
7158.195.0.0/17158.195.0.1 to 158.195.127.254158.195.127.25532,766
8158.195.128.0/17158.195.128.1 to 158.195.255.254158.195.255.25532,766
9158.196.0.0/17158.196.0.1 to 158.196.127.254158.196.127.25532,766
10158.196.128.0/17158.196.128.1 to 158.196.255.254158.196.255.25532,766
11158.197.0.0/17158.197.0.1 to 158.197.127.254158.197.127.25532,766
12158.197.128.0/17158.197.128.1 to 158.197.255.254158.197.255.25532,766
13158.198.0.0/17158.198.0.1 to 158.198.127.254158.198.127.25532,766
14158.198.128.0/17158.198.128.1 to 158.198.255.254158.198.255.25532,766
15158.199.0.0/17158.199.0.1 to 158.199.127.254158.199.127.25532,766
16158.199.128.0/17158.199.128.1 to 158.199.255.254158.199.255.25532,766
17158.200.0.0/17158.200.0.1 to 158.200.127.254158.200.127.25532,766
18158.200.128.0/17158.200.128.1 to 158.200.255.254158.200.255.25532,766
19158.201.0.0/17158.201.0.1 to 158.201.127.254158.201.127.25532,766
20158.201.128.0/17158.201.128.1 to 158.201.255.254158.201.255.25532,766
21158.202.0.0/17158.202.0.1 to 158.202.127.254158.202.127.25532,766
22158.202.128.0/17158.202.128.1 to 158.202.255.254158.202.255.25532,766
23158.203.0.0/17158.203.0.1 to 158.203.127.254158.203.127.25532,766
24158.203.128.0/17158.203.128.1 to 158.203.255.254158.203.255.25532,766
25158.204.0.0/17158.204.0.1 to 158.204.127.254158.204.127.25532,766
26158.204.128.0/17158.204.128.1 to 158.204.255.254158.204.255.25532,766
27158.205.0.0/17158.205.0.1 to 158.205.127.254158.205.127.25532,766
28158.205.128.0/17158.205.128.1 to 158.205.255.254158.205.255.25532,766
29158.206.0.0/17158.206.0.1 to 158.206.127.254158.206.127.25532,766
30158.206.128.0/17158.206.128.1 to 158.206.255.254158.206.255.25532,766
31158.207.0.0/17158.207.0.1 to 158.207.127.254158.207.127.25532,766
32158.207.128.0/17158.207.128.1 to 158.207.255.254158.207.255.25532,766
33158.208.0.0/17158.208.0.1 to 158.208.127.254158.208.127.25532,766
34158.208.128.0/17158.208.128.1 to 158.208.255.254158.208.255.25532,766
35158.209.0.0/17158.209.0.1 to 158.209.127.254158.209.127.25532,766
36158.209.128.0/17158.209.128.1 to 158.209.255.254158.209.255.25532,766
37158.210.0.0/17158.210.0.1 to 158.210.127.254158.210.127.25532,766
38158.210.128.0/17158.210.128.1 to 158.210.255.254158.210.255.25532,766
39158.211.0.0/17158.211.0.1 to 158.211.127.254158.211.127.25532,766
40158.211.128.0/17158.211.128.1 to 158.211.255.254158.211.255.25532,766
41158.212.0.0/17158.212.0.1 to 158.212.127.254158.212.127.25532,766
42158.212.128.0/17158.212.128.1 to 158.212.255.254158.212.255.25532,766
43158.213.0.0/17158.213.0.1 to 158.213.127.254158.213.127.25532,766
44158.213.128.0/17158.213.128.1 to 158.213.255.254158.213.255.25532,766
45158.214.0.0/17158.214.0.1 to 158.214.127.254158.214.127.25532,766
46158.214.128.0/17158.214.128.1 to 158.214.255.254158.214.255.25532,766
47158.215.0.0/17158.215.0.1 to 158.215.127.254158.215.127.25532,766
48158.215.128.0/17158.215.128.1 to 158.215.255.254158.215.255.25532,766
49158.216.0.0/17158.216.0.1 to 158.216.127.254158.216.127.25532,766
50158.216.128.0/17158.216.128.1 to 158.216.255.254158.216.255.25532,766
51158.217.0.0/17158.217.0.1 to 158.217.127.254158.217.127.25532,766
52158.217.128.0/17158.217.128.1 to 158.217.255.254158.217.255.25532,766
53158.218.0.0/17158.218.0.1 to 158.218.127.254158.218.127.25532,766
54158.218.128.0/17158.218.128.1 to 158.218.255.254158.218.255.25532,766
55158.219.0.0/17158.219.0.1 to 158.219.127.254158.219.127.25532,766
56158.219.128.0/17158.219.128.1 to 158.219.255.254158.219.255.25532,766
57158.220.0.0/17158.220.0.1 to 158.220.127.254158.220.127.25532,766
58158.220.128.0/17158.220.128.1 to 158.220.255.254158.220.255.25532,766
59158.221.0.0/17158.221.0.1 to 158.221.127.254158.221.127.25532,766
60158.221.128.0/17158.221.128.1 to 158.221.255.254158.221.255.25532,766
61158.222.0.0/17158.222.0.1 to 158.222.127.254158.222.127.25532,766
62158.222.128.0/17158.222.128.1 to 158.222.255.254158.222.255.25532,766
63158.223.0.0/17158.223.0.1 to 158.223.127.254158.223.127.25532,766
64158.223.128.0/17158.223.128.1 to 158.223.255.254158.223.255.25532,766
65158.224.0.0/17158.224.0.1 to 158.224.127.254158.224.127.25532,766
66158.224.128.0/17158.224.128.1 to 158.224.255.254158.224.255.25532,766
67158.225.0.0/17158.225.0.1 to 158.225.127.254158.225.127.25532,766
68158.225.128.0/17158.225.128.1 to 158.225.255.254158.225.255.25532,766
69158.226.0.0/17158.226.0.1 to 158.226.127.254158.226.127.25532,766
70158.226.128.0/17158.226.128.1 to 158.226.255.254158.226.255.25532,766
71158.227.0.0/17158.227.0.1 to 158.227.127.254158.227.127.25532,766
72158.227.128.0/17158.227.128.1 to 158.227.255.254158.227.255.25532,766
73158.228.0.0/17158.228.0.1 to 158.228.127.254158.228.127.25532,766
74158.228.128.0/17158.228.128.1 to 158.228.255.254158.228.255.25532,766
75158.229.0.0/17158.229.0.1 to 158.229.127.254158.229.127.25532,766
76158.229.128.0/17158.229.128.1 to 158.229.255.254158.229.255.25532,766
77158.230.0.0/17158.230.0.1 to 158.230.127.254158.230.127.25532,766
78158.230.128.0/17158.230.128.1 to 158.230.255.254158.230.255.25532,766
79158.231.0.0/17158.231.0.1 to 158.231.127.254158.231.127.25532,766
80158.231.128.0/17158.231.128.1 to 158.231.255.254158.231.255.25532,766
81158.232.0.0/17158.232.0.1 to 158.232.127.254158.232.127.25532,766
82158.232.128.0/17158.232.128.1 to 158.232.255.254158.232.255.25532,766
83158.233.0.0/17158.233.0.1 to 158.233.127.254158.233.127.25532,766
84158.233.128.0/17158.233.128.1 to 158.233.255.254158.233.255.25532,766
85158.234.0.0/17158.234.0.1 to 158.234.127.254158.234.127.25532,766
86158.234.128.0/17158.234.128.1 to 158.234.255.254158.234.255.25532,766
87158.235.0.0/17158.235.0.1 to 158.235.127.254158.235.127.25532,766
88158.235.128.0/17158.235.128.1 to 158.235.255.254158.235.255.25532,766
89158.236.0.0/17158.236.0.1 to 158.236.127.254158.236.127.25532,766
90158.236.128.0/17158.236.128.1 to 158.236.255.254158.236.255.25532,766
91158.237.0.0/17158.237.0.1 to 158.237.127.254158.237.127.25532,766
92158.237.128.0/17158.237.128.1 to 158.237.255.254158.237.255.25532,766
93158.238.0.0/17158.238.0.1 to 158.238.127.254158.238.127.25532,766
94158.238.128.0/17158.238.128.1 to 158.238.255.254158.238.255.25532,766
95158.239.0.0/17158.239.0.1 to 158.239.127.254158.239.127.25532,766
96158.239.128.0/17158.239.128.1 to 158.239.255.254158.239.255.25532,766
97158.240.0.0/17158.240.0.1 to 158.240.127.254158.240.127.25532,766
98158.240.128.0/17158.240.128.1 to 158.240.255.254158.240.255.25532,766
99158.241.0.0/17158.241.0.1 to 158.241.127.254158.241.127.25532,766
100158.241.128.0/17158.241.128.1 to 158.241.255.254158.241.255.25532,766
101158.242.0.0/17158.242.0.1 to 158.242.127.254158.242.127.25532,766
102158.242.128.0/17158.242.128.1 to 158.242.255.254158.242.255.25532,766
103158.243.0.0/17158.243.0.1 to 158.243.127.254158.243.127.25532,766
104158.243.128.0/17158.243.128.1 to 158.243.255.254158.243.255.25532,766
105158.244.0.0/17158.244.0.1 to 158.244.127.254158.244.127.25532,766
106158.244.128.0/17158.244.128.1 to 158.244.255.254158.244.255.25532,766
107158.245.0.0/17158.245.0.1 to 158.245.127.254158.245.127.25532,766
108158.245.128.0/17158.245.128.1 to 158.245.255.254158.245.255.25532,766
109158.246.0.0/17158.246.0.1 to 158.246.127.254158.246.127.25532,766
110158.246.128.0/17158.246.128.1 to 158.246.255.254158.246.255.25532,766
111158.247.0.0/17158.247.0.1 to 158.247.127.254158.247.127.25532,766
112158.247.128.0/17158.247.128.1 to 158.247.255.254158.247.255.25532,766
113158.248.0.0/17158.248.0.1 to 158.248.127.254158.248.127.25532,766
114158.248.128.0/17158.248.128.1 to 158.248.255.254158.248.255.25532,766
115158.249.0.0/17158.249.0.1 to 158.249.127.254158.249.127.25532,766
116158.249.128.0/17158.249.128.1 to 158.249.255.254158.249.255.25532,766
117158.250.0.0/17158.250.0.1 to 158.250.127.254158.250.127.25532,766
118158.250.128.0/17158.250.128.1 to 158.250.255.254158.250.255.25532,766
119158.251.0.0/17158.251.0.1 to 158.251.127.254158.251.127.25532,766
120158.251.128.0/17158.251.128.1 to 158.251.255.254158.251.255.25532,766
121158.252.0.0/17158.252.0.1 to 158.252.127.254158.252.127.25532,766
122158.252.128.0/17158.252.128.1 to 158.252.255.254158.252.255.25532,766
123158.253.0.0/17158.253.0.1 to 158.253.127.254158.253.127.25532,766
124158.253.128.0/17158.253.128.1 to 158.253.255.254158.253.255.25532,766
125158.254.0.0/17158.254.0.1 to 158.254.127.254158.254.127.25532,766
126158.254.128.0/17158.254.128.1 to 158.254.255.254158.254.255.25532,766
127158.255.0.0/17158.255.0.1 to 158.255.127.254158.255.127.25532,766
128158.255.128.0/17158.255.128.1 to 158.255.255.254158.255.255.25532,766

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.