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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.

Network150.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
150.0.0.0
Broadcast address
151.255.255.255
First usable
150.0.0.1
Last usable
151.255.255.254
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
Public public
Old class
B (default /16)
As numbers
Hex 96000000 · Integer 2516582400 to 2550136831
Reverse DNS zones
150.in-addr.arpa
151.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
Address10010110.00000000.00000000.00000000150.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10010110.00000000.00000000.00000000150.0.0.0
Broadcast10010111.11111111.11111111.11111111151.255.255.255
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)

150.0.0.0/7 makes 128 subnets of /14.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1150.0.0.0/14150.0.0.1 to 150.3.255.254150.3.255.255262,142
2150.4.0.0/14150.4.0.1 to 150.7.255.254150.7.255.255262,142
3150.8.0.0/14150.8.0.1 to 150.11.255.254150.11.255.255262,142
4150.12.0.0/14150.12.0.1 to 150.15.255.254150.15.255.255262,142
5150.16.0.0/14150.16.0.1 to 150.19.255.254150.19.255.255262,142
6150.20.0.0/14150.20.0.1 to 150.23.255.254150.23.255.255262,142
7150.24.0.0/14150.24.0.1 to 150.27.255.254150.27.255.255262,142
8150.28.0.0/14150.28.0.1 to 150.31.255.254150.31.255.255262,142
9150.32.0.0/14150.32.0.1 to 150.35.255.254150.35.255.255262,142
10150.36.0.0/14150.36.0.1 to 150.39.255.254150.39.255.255262,142
11150.40.0.0/14150.40.0.1 to 150.43.255.254150.43.255.255262,142
12150.44.0.0/14150.44.0.1 to 150.47.255.254150.47.255.255262,142
13150.48.0.0/14150.48.0.1 to 150.51.255.254150.51.255.255262,142
14150.52.0.0/14150.52.0.1 to 150.55.255.254150.55.255.255262,142
15150.56.0.0/14150.56.0.1 to 150.59.255.254150.59.255.255262,142
16150.60.0.0/14150.60.0.1 to 150.63.255.254150.63.255.255262,142
17150.64.0.0/14150.64.0.1 to 150.67.255.254150.67.255.255262,142
18150.68.0.0/14150.68.0.1 to 150.71.255.254150.71.255.255262,142
19150.72.0.0/14150.72.0.1 to 150.75.255.254150.75.255.255262,142
20150.76.0.0/14150.76.0.1 to 150.79.255.254150.79.255.255262,142
21150.80.0.0/14150.80.0.1 to 150.83.255.254150.83.255.255262,142
22150.84.0.0/14150.84.0.1 to 150.87.255.254150.87.255.255262,142
23150.88.0.0/14150.88.0.1 to 150.91.255.254150.91.255.255262,142
24150.92.0.0/14150.92.0.1 to 150.95.255.254150.95.255.255262,142
25150.96.0.0/14150.96.0.1 to 150.99.255.254150.99.255.255262,142
26150.100.0.0/14150.100.0.1 to 150.103.255.254150.103.255.255262,142
27150.104.0.0/14150.104.0.1 to 150.107.255.254150.107.255.255262,142
28150.108.0.0/14150.108.0.1 to 150.111.255.254150.111.255.255262,142
29150.112.0.0/14150.112.0.1 to 150.115.255.254150.115.255.255262,142
30150.116.0.0/14150.116.0.1 to 150.119.255.254150.119.255.255262,142
31150.120.0.0/14150.120.0.1 to 150.123.255.254150.123.255.255262,142
32150.124.0.0/14150.124.0.1 to 150.127.255.254150.127.255.255262,142
33150.128.0.0/14150.128.0.1 to 150.131.255.254150.131.255.255262,142
34150.132.0.0/14150.132.0.1 to 150.135.255.254150.135.255.255262,142
35150.136.0.0/14150.136.0.1 to 150.139.255.254150.139.255.255262,142
36150.140.0.0/14150.140.0.1 to 150.143.255.254150.143.255.255262,142
37150.144.0.0/14150.144.0.1 to 150.147.255.254150.147.255.255262,142
38150.148.0.0/14150.148.0.1 to 150.151.255.254150.151.255.255262,142
39150.152.0.0/14150.152.0.1 to 150.155.255.254150.155.255.255262,142
40150.156.0.0/14150.156.0.1 to 150.159.255.254150.159.255.255262,142
41150.160.0.0/14150.160.0.1 to 150.163.255.254150.163.255.255262,142
42150.164.0.0/14150.164.0.1 to 150.167.255.254150.167.255.255262,142
43150.168.0.0/14150.168.0.1 to 150.171.255.254150.171.255.255262,142
44150.172.0.0/14150.172.0.1 to 150.175.255.254150.175.255.255262,142
45150.176.0.0/14150.176.0.1 to 150.179.255.254150.179.255.255262,142
46150.180.0.0/14150.180.0.1 to 150.183.255.254150.183.255.255262,142
47150.184.0.0/14150.184.0.1 to 150.187.255.254150.187.255.255262,142
48150.188.0.0/14150.188.0.1 to 150.191.255.254150.191.255.255262,142
49150.192.0.0/14150.192.0.1 to 150.195.255.254150.195.255.255262,142
50150.196.0.0/14150.196.0.1 to 150.199.255.254150.199.255.255262,142
51150.200.0.0/14150.200.0.1 to 150.203.255.254150.203.255.255262,142
52150.204.0.0/14150.204.0.1 to 150.207.255.254150.207.255.255262,142
53150.208.0.0/14150.208.0.1 to 150.211.255.254150.211.255.255262,142
54150.212.0.0/14150.212.0.1 to 150.215.255.254150.215.255.255262,142
55150.216.0.0/14150.216.0.1 to 150.219.255.254150.219.255.255262,142
56150.220.0.0/14150.220.0.1 to 150.223.255.254150.223.255.255262,142
57150.224.0.0/14150.224.0.1 to 150.227.255.254150.227.255.255262,142
58150.228.0.0/14150.228.0.1 to 150.231.255.254150.231.255.255262,142
59150.232.0.0/14150.232.0.1 to 150.235.255.254150.235.255.255262,142
60150.236.0.0/14150.236.0.1 to 150.239.255.254150.239.255.255262,142
61150.240.0.0/14150.240.0.1 to 150.243.255.254150.243.255.255262,142
62150.244.0.0/14150.244.0.1 to 150.247.255.254150.247.255.255262,142
63150.248.0.0/14150.248.0.1 to 150.251.255.254150.251.255.255262,142
64150.252.0.0/14150.252.0.1 to 150.255.255.254150.255.255.255262,142
65151.0.0.0/14151.0.0.1 to 151.3.255.254151.3.255.255262,142
66151.4.0.0/14151.4.0.1 to 151.7.255.254151.7.255.255262,142
67151.8.0.0/14151.8.0.1 to 151.11.255.254151.11.255.255262,142
68151.12.0.0/14151.12.0.1 to 151.15.255.254151.15.255.255262,142
69151.16.0.0/14151.16.0.1 to 151.19.255.254151.19.255.255262,142
70151.20.0.0/14151.20.0.1 to 151.23.255.254151.23.255.255262,142
71151.24.0.0/14151.24.0.1 to 151.27.255.254151.27.255.255262,142
72151.28.0.0/14151.28.0.1 to 151.31.255.254151.31.255.255262,142
73151.32.0.0/14151.32.0.1 to 151.35.255.254151.35.255.255262,142
74151.36.0.0/14151.36.0.1 to 151.39.255.254151.39.255.255262,142
75151.40.0.0/14151.40.0.1 to 151.43.255.254151.43.255.255262,142
76151.44.0.0/14151.44.0.1 to 151.47.255.254151.47.255.255262,142
77151.48.0.0/14151.48.0.1 to 151.51.255.254151.51.255.255262,142
78151.52.0.0/14151.52.0.1 to 151.55.255.254151.55.255.255262,142
79151.56.0.0/14151.56.0.1 to 151.59.255.254151.59.255.255262,142
80151.60.0.0/14151.60.0.1 to 151.63.255.254151.63.255.255262,142
81151.64.0.0/14151.64.0.1 to 151.67.255.254151.67.255.255262,142
82151.68.0.0/14151.68.0.1 to 151.71.255.254151.71.255.255262,142
83151.72.0.0/14151.72.0.1 to 151.75.255.254151.75.255.255262,142
84151.76.0.0/14151.76.0.1 to 151.79.255.254151.79.255.255262,142
85151.80.0.0/14151.80.0.1 to 151.83.255.254151.83.255.255262,142
86151.84.0.0/14151.84.0.1 to 151.87.255.254151.87.255.255262,142
87151.88.0.0/14151.88.0.1 to 151.91.255.254151.91.255.255262,142
88151.92.0.0/14151.92.0.1 to 151.95.255.254151.95.255.255262,142
89151.96.0.0/14151.96.0.1 to 151.99.255.254151.99.255.255262,142
90151.100.0.0/14151.100.0.1 to 151.103.255.254151.103.255.255262,142
91151.104.0.0/14151.104.0.1 to 151.107.255.254151.107.255.255262,142
92151.108.0.0/14151.108.0.1 to 151.111.255.254151.111.255.255262,142
93151.112.0.0/14151.112.0.1 to 151.115.255.254151.115.255.255262,142
94151.116.0.0/14151.116.0.1 to 151.119.255.254151.119.255.255262,142
95151.120.0.0/14151.120.0.1 to 151.123.255.254151.123.255.255262,142
96151.124.0.0/14151.124.0.1 to 151.127.255.254151.127.255.255262,142
97151.128.0.0/14151.128.0.1 to 151.131.255.254151.131.255.255262,142
98151.132.0.0/14151.132.0.1 to 151.135.255.254151.135.255.255262,142
99151.136.0.0/14151.136.0.1 to 151.139.255.254151.139.255.255262,142
100151.140.0.0/14151.140.0.1 to 151.143.255.254151.143.255.255262,142
101151.144.0.0/14151.144.0.1 to 151.147.255.254151.147.255.255262,142
102151.148.0.0/14151.148.0.1 to 151.151.255.254151.151.255.255262,142
103151.152.0.0/14151.152.0.1 to 151.155.255.254151.155.255.255262,142
104151.156.0.0/14151.156.0.1 to 151.159.255.254151.159.255.255262,142
105151.160.0.0/14151.160.0.1 to 151.163.255.254151.163.255.255262,142
106151.164.0.0/14151.164.0.1 to 151.167.255.254151.167.255.255262,142
107151.168.0.0/14151.168.0.1 to 151.171.255.254151.171.255.255262,142
108151.172.0.0/14151.172.0.1 to 151.175.255.254151.175.255.255262,142
109151.176.0.0/14151.176.0.1 to 151.179.255.254151.179.255.255262,142
110151.180.0.0/14151.180.0.1 to 151.183.255.254151.183.255.255262,142
111151.184.0.0/14151.184.0.1 to 151.187.255.254151.187.255.255262,142
112151.188.0.0/14151.188.0.1 to 151.191.255.254151.191.255.255262,142
113151.192.0.0/14151.192.0.1 to 151.195.255.254151.195.255.255262,142
114151.196.0.0/14151.196.0.1 to 151.199.255.254151.199.255.255262,142
115151.200.0.0/14151.200.0.1 to 151.203.255.254151.203.255.255262,142
116151.204.0.0/14151.204.0.1 to 151.207.255.254151.207.255.255262,142
117151.208.0.0/14151.208.0.1 to 151.211.255.254151.211.255.255262,142
118151.212.0.0/14151.212.0.1 to 151.215.255.254151.215.255.255262,142
119151.216.0.0/14151.216.0.1 to 151.219.255.254151.219.255.255262,142
120151.220.0.0/14151.220.0.1 to 151.223.255.254151.223.255.255262,142
121151.224.0.0/14151.224.0.1 to 151.227.255.254151.227.255.255262,142
122151.228.0.0/14151.228.0.1 to 151.231.255.254151.231.255.255262,142
123151.232.0.0/14151.232.0.1 to 151.235.255.254151.235.255.255262,142
124151.236.0.0/14151.236.0.1 to 151.239.255.254151.239.255.255262,142
125151.240.0.0/14151.240.0.1 to 151.243.255.254151.243.255.255262,142
126151.244.0.0/14151.244.0.1 to 151.247.255.254151.247.255.255262,142
127151.248.0.0/14151.248.0.1 to 151.251.255.254151.251.255.255262,142
128151.252.0.0/14151.252.0.1 to 151.255.255.254151.255.255.255262,142

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.