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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.

Network150.0.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
150.0.0.0
Broadcast address
150.1.255.255
First usable
150.0.0.1
Last usable
150.1.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex 96000000 · Integer 2516582400 to 2516713471
Reverse DNS zones
0.150.in-addr.arpa
1.150.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10010110.00000000.00000000.00000000150.0.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10010110.00000000.00000000.00000000150.0.0.0
Broadcast10010110.00000001.11111111.11111111150.1.255.255
Split into smaller subnets/22
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

150.0.0.0/15 makes 128 subnets of /22.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1150.0.0.0/22150.0.0.1 to 150.0.3.254150.0.3.2551,022
2150.0.4.0/22150.0.4.1 to 150.0.7.254150.0.7.2551,022
3150.0.8.0/22150.0.8.1 to 150.0.11.254150.0.11.2551,022
4150.0.12.0/22150.0.12.1 to 150.0.15.254150.0.15.2551,022
5150.0.16.0/22150.0.16.1 to 150.0.19.254150.0.19.2551,022
6150.0.20.0/22150.0.20.1 to 150.0.23.254150.0.23.2551,022
7150.0.24.0/22150.0.24.1 to 150.0.27.254150.0.27.2551,022
8150.0.28.0/22150.0.28.1 to 150.0.31.254150.0.31.2551,022
9150.0.32.0/22150.0.32.1 to 150.0.35.254150.0.35.2551,022
10150.0.36.0/22150.0.36.1 to 150.0.39.254150.0.39.2551,022
11150.0.40.0/22150.0.40.1 to 150.0.43.254150.0.43.2551,022
12150.0.44.0/22150.0.44.1 to 150.0.47.254150.0.47.2551,022
13150.0.48.0/22150.0.48.1 to 150.0.51.254150.0.51.2551,022
14150.0.52.0/22150.0.52.1 to 150.0.55.254150.0.55.2551,022
15150.0.56.0/22150.0.56.1 to 150.0.59.254150.0.59.2551,022
16150.0.60.0/22150.0.60.1 to 150.0.63.254150.0.63.2551,022
17150.0.64.0/22150.0.64.1 to 150.0.67.254150.0.67.2551,022
18150.0.68.0/22150.0.68.1 to 150.0.71.254150.0.71.2551,022
19150.0.72.0/22150.0.72.1 to 150.0.75.254150.0.75.2551,022
20150.0.76.0/22150.0.76.1 to 150.0.79.254150.0.79.2551,022
21150.0.80.0/22150.0.80.1 to 150.0.83.254150.0.83.2551,022
22150.0.84.0/22150.0.84.1 to 150.0.87.254150.0.87.2551,022
23150.0.88.0/22150.0.88.1 to 150.0.91.254150.0.91.2551,022
24150.0.92.0/22150.0.92.1 to 150.0.95.254150.0.95.2551,022
25150.0.96.0/22150.0.96.1 to 150.0.99.254150.0.99.2551,022
26150.0.100.0/22150.0.100.1 to 150.0.103.254150.0.103.2551,022
27150.0.104.0/22150.0.104.1 to 150.0.107.254150.0.107.2551,022
28150.0.108.0/22150.0.108.1 to 150.0.111.254150.0.111.2551,022
29150.0.112.0/22150.0.112.1 to 150.0.115.254150.0.115.2551,022
30150.0.116.0/22150.0.116.1 to 150.0.119.254150.0.119.2551,022
31150.0.120.0/22150.0.120.1 to 150.0.123.254150.0.123.2551,022
32150.0.124.0/22150.0.124.1 to 150.0.127.254150.0.127.2551,022
33150.0.128.0/22150.0.128.1 to 150.0.131.254150.0.131.2551,022
34150.0.132.0/22150.0.132.1 to 150.0.135.254150.0.135.2551,022
35150.0.136.0/22150.0.136.1 to 150.0.139.254150.0.139.2551,022
36150.0.140.0/22150.0.140.1 to 150.0.143.254150.0.143.2551,022
37150.0.144.0/22150.0.144.1 to 150.0.147.254150.0.147.2551,022
38150.0.148.0/22150.0.148.1 to 150.0.151.254150.0.151.2551,022
39150.0.152.0/22150.0.152.1 to 150.0.155.254150.0.155.2551,022
40150.0.156.0/22150.0.156.1 to 150.0.159.254150.0.159.2551,022
41150.0.160.0/22150.0.160.1 to 150.0.163.254150.0.163.2551,022
42150.0.164.0/22150.0.164.1 to 150.0.167.254150.0.167.2551,022
43150.0.168.0/22150.0.168.1 to 150.0.171.254150.0.171.2551,022
44150.0.172.0/22150.0.172.1 to 150.0.175.254150.0.175.2551,022
45150.0.176.0/22150.0.176.1 to 150.0.179.254150.0.179.2551,022
46150.0.180.0/22150.0.180.1 to 150.0.183.254150.0.183.2551,022
47150.0.184.0/22150.0.184.1 to 150.0.187.254150.0.187.2551,022
48150.0.188.0/22150.0.188.1 to 150.0.191.254150.0.191.2551,022
49150.0.192.0/22150.0.192.1 to 150.0.195.254150.0.195.2551,022
50150.0.196.0/22150.0.196.1 to 150.0.199.254150.0.199.2551,022
51150.0.200.0/22150.0.200.1 to 150.0.203.254150.0.203.2551,022
52150.0.204.0/22150.0.204.1 to 150.0.207.254150.0.207.2551,022
53150.0.208.0/22150.0.208.1 to 150.0.211.254150.0.211.2551,022
54150.0.212.0/22150.0.212.1 to 150.0.215.254150.0.215.2551,022
55150.0.216.0/22150.0.216.1 to 150.0.219.254150.0.219.2551,022
56150.0.220.0/22150.0.220.1 to 150.0.223.254150.0.223.2551,022
57150.0.224.0/22150.0.224.1 to 150.0.227.254150.0.227.2551,022
58150.0.228.0/22150.0.228.1 to 150.0.231.254150.0.231.2551,022
59150.0.232.0/22150.0.232.1 to 150.0.235.254150.0.235.2551,022
60150.0.236.0/22150.0.236.1 to 150.0.239.254150.0.239.2551,022
61150.0.240.0/22150.0.240.1 to 150.0.243.254150.0.243.2551,022
62150.0.244.0/22150.0.244.1 to 150.0.247.254150.0.247.2551,022
63150.0.248.0/22150.0.248.1 to 150.0.251.254150.0.251.2551,022
64150.0.252.0/22150.0.252.1 to 150.0.255.254150.0.255.2551,022
65150.1.0.0/22150.1.0.1 to 150.1.3.254150.1.3.2551,022
66150.1.4.0/22150.1.4.1 to 150.1.7.254150.1.7.2551,022
67150.1.8.0/22150.1.8.1 to 150.1.11.254150.1.11.2551,022
68150.1.12.0/22150.1.12.1 to 150.1.15.254150.1.15.2551,022
69150.1.16.0/22150.1.16.1 to 150.1.19.254150.1.19.2551,022
70150.1.20.0/22150.1.20.1 to 150.1.23.254150.1.23.2551,022
71150.1.24.0/22150.1.24.1 to 150.1.27.254150.1.27.2551,022
72150.1.28.0/22150.1.28.1 to 150.1.31.254150.1.31.2551,022
73150.1.32.0/22150.1.32.1 to 150.1.35.254150.1.35.2551,022
74150.1.36.0/22150.1.36.1 to 150.1.39.254150.1.39.2551,022
75150.1.40.0/22150.1.40.1 to 150.1.43.254150.1.43.2551,022
76150.1.44.0/22150.1.44.1 to 150.1.47.254150.1.47.2551,022
77150.1.48.0/22150.1.48.1 to 150.1.51.254150.1.51.2551,022
78150.1.52.0/22150.1.52.1 to 150.1.55.254150.1.55.2551,022
79150.1.56.0/22150.1.56.1 to 150.1.59.254150.1.59.2551,022
80150.1.60.0/22150.1.60.1 to 150.1.63.254150.1.63.2551,022
81150.1.64.0/22150.1.64.1 to 150.1.67.254150.1.67.2551,022
82150.1.68.0/22150.1.68.1 to 150.1.71.254150.1.71.2551,022
83150.1.72.0/22150.1.72.1 to 150.1.75.254150.1.75.2551,022
84150.1.76.0/22150.1.76.1 to 150.1.79.254150.1.79.2551,022
85150.1.80.0/22150.1.80.1 to 150.1.83.254150.1.83.2551,022
86150.1.84.0/22150.1.84.1 to 150.1.87.254150.1.87.2551,022
87150.1.88.0/22150.1.88.1 to 150.1.91.254150.1.91.2551,022
88150.1.92.0/22150.1.92.1 to 150.1.95.254150.1.95.2551,022
89150.1.96.0/22150.1.96.1 to 150.1.99.254150.1.99.2551,022
90150.1.100.0/22150.1.100.1 to 150.1.103.254150.1.103.2551,022
91150.1.104.0/22150.1.104.1 to 150.1.107.254150.1.107.2551,022
92150.1.108.0/22150.1.108.1 to 150.1.111.254150.1.111.2551,022
93150.1.112.0/22150.1.112.1 to 150.1.115.254150.1.115.2551,022
94150.1.116.0/22150.1.116.1 to 150.1.119.254150.1.119.2551,022
95150.1.120.0/22150.1.120.1 to 150.1.123.254150.1.123.2551,022
96150.1.124.0/22150.1.124.1 to 150.1.127.254150.1.127.2551,022
97150.1.128.0/22150.1.128.1 to 150.1.131.254150.1.131.2551,022
98150.1.132.0/22150.1.132.1 to 150.1.135.254150.1.135.2551,022
99150.1.136.0/22150.1.136.1 to 150.1.139.254150.1.139.2551,022
100150.1.140.0/22150.1.140.1 to 150.1.143.254150.1.143.2551,022
101150.1.144.0/22150.1.144.1 to 150.1.147.254150.1.147.2551,022
102150.1.148.0/22150.1.148.1 to 150.1.151.254150.1.151.2551,022
103150.1.152.0/22150.1.152.1 to 150.1.155.254150.1.155.2551,022
104150.1.156.0/22150.1.156.1 to 150.1.159.254150.1.159.2551,022
105150.1.160.0/22150.1.160.1 to 150.1.163.254150.1.163.2551,022
106150.1.164.0/22150.1.164.1 to 150.1.167.254150.1.167.2551,022
107150.1.168.0/22150.1.168.1 to 150.1.171.254150.1.171.2551,022
108150.1.172.0/22150.1.172.1 to 150.1.175.254150.1.175.2551,022
109150.1.176.0/22150.1.176.1 to 150.1.179.254150.1.179.2551,022
110150.1.180.0/22150.1.180.1 to 150.1.183.254150.1.183.2551,022
111150.1.184.0/22150.1.184.1 to 150.1.187.254150.1.187.2551,022
112150.1.188.0/22150.1.188.1 to 150.1.191.254150.1.191.2551,022
113150.1.192.0/22150.1.192.1 to 150.1.195.254150.1.195.2551,022
114150.1.196.0/22150.1.196.1 to 150.1.199.254150.1.199.2551,022
115150.1.200.0/22150.1.200.1 to 150.1.203.254150.1.203.2551,022
116150.1.204.0/22150.1.204.1 to 150.1.207.254150.1.207.2551,022
117150.1.208.0/22150.1.208.1 to 150.1.211.254150.1.211.2551,022
118150.1.212.0/22150.1.212.1 to 150.1.215.254150.1.215.2551,022
119150.1.216.0/22150.1.216.1 to 150.1.219.254150.1.219.2551,022
120150.1.220.0/22150.1.220.1 to 150.1.223.254150.1.223.2551,022
121150.1.224.0/22150.1.224.1 to 150.1.227.254150.1.227.2551,022
122150.1.228.0/22150.1.228.1 to 150.1.231.254150.1.231.2551,022
123150.1.232.0/22150.1.232.1 to 150.1.235.254150.1.235.2551,022
124150.1.236.0/22150.1.236.1 to 150.1.239.254150.1.239.2551,022
125150.1.240.0/22150.1.240.1 to 150.1.243.254150.1.243.2551,022
126150.1.244.0/22150.1.244.1 to 150.1.247.254150.1.247.2551,022
127150.1.248.0/22150.1.248.1 to 150.1.251.254150.1.251.2551,022
128150.1.252.0/22150.1.252.1 to 150.1.255.254150.1.255.2551,022

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.